阅读说明：本技术 一种秸秆好氧发酵热肥联产工艺 (Straw aerobic fermentation heat and fertilizer co-production process ) 是由 于艳玲 许磊 曹永娜 刘净伊 于 2021-08-28 设计创作，主要内容包括：本发明公开了一种秸秆好氧发酵热肥联产工艺,包括以下步骤：(1)将秸秆进行粉碎；(2)将经过预处理的秸秆铺设在发酵容器底部,然后将氮源、磷源、pH调节剂和水充分混合后播撒在秸秆层表面,将秸秆与所有物质混合均匀,混匀后再在表面依次播撒易腐物质、混合菌剂与水的混合液；(3)播撒完毕后重复步骤(2),直至发酵容器被填满；(4)将经过发酵后的秸秆取出,自然风干至含水率在30％以下,粉碎至颗粒状即可。本发明主要是以秸秆为发酵原料的产热、肥工艺,相对于同类工艺技术,本发明方法能量输出模式更多元,秸秆的利用方式更全面,可以增加好氧发酵的产热量,便于规模化、机械化施工,肥效较好。(The invention discloses a straw aerobic fermentation heat and fertilizer co-production process, which comprises the following steps: (1) crushing the straws; (2) laying the pretreated straws at the bottom of a fermentation container, then fully mixing a nitrogen source, a phosphorus source, a pH regulator and water, then spreading the mixture on the surface of a straw layer, uniformly mixing the straws and all substances, and then sequentially spreading a mixed solution of a perishable substance, a mixed microbial inoculum and water on the surface after uniformly mixing; (3) repeating the step (2) after the sowing is finished until the fermentation container is filled; (4) taking out the fermented straws, naturally drying until the water content is below 30%, and pulverizing into granules. The invention mainly uses straws as fermentation raw materials to produce heat and fertilizer, and compared with the similar process technology, the method has more diversified energy output modes and more comprehensive utilization modes of the straws, can increase the heat production of aerobic fermentation, is convenient for large-scale and mechanized construction, and has better fertilizer efficiency.)

1. A straw aerobic fermentation heat and fertilizer co-production process is characterized by comprising the following steps:

(1) straw pretreatment: pulverizing straw to 50-100kg/cm³；

(2) Fermentation construction: laying the pretreated straws at the bottom of a fermentation container, taking 20-40cm as a layer, fully mixing a nitrogen source, a phosphorus source, a pH regulator and water, then spreading the mixture on the surface of the straw layer, uniformly mixing the straws and all substances, and then sequentially spreading mixed liquid of perishable substances, mixed microbial inoculum and water on the surface;

(3) repeating the step (2) after the sowing is finished until the fermentation container is filled;

(4) preparing a fertilizer: taking out the fermented straws, naturally drying until the water content is below 30%, and crushing into granules;

the fermentation process is carried out by heat taking and cooling process, specifically, a water pipe is arranged at the center of the fermentation pile body, and the water pipe is arranged every 1m²Placing a water pipe with the length of more than 3m, driving the circulation power by a water pump to circulate, and controlling the water inlet temperature to be between 5 and 50 ℃.

2. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1, wherein the mass ratio of the straw, the nitrogen source, the phosphorus source, the pH regulator, the perishable material and the water in the step (2) is 1000: (30-40): (40-70): (10-15): (10-30): 1000, and the ratio of the straws to the mixed microbial inoculum is 5 ml: (1-2) kg.

3. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1 or 2, wherein the mixed microbial inoculum comprises 50% of EM (effective viable count) bacteria, 35-45% of lactobacillus, 3-5% of bacillus, 0.2-0.4% of Burkholderia, 0.3-0.4% of Ralstonia, 0.2-0.5% of Acinetobacter and 0.1-0.3% of Acetobacter, and the effective viable count of the mixed microbial inoculum is more than 1 x 10¹⁰One per ml.

4. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1 or 2, wherein the nitrogen source is added in a carbon-nitrogen ratio of 10-30 as a standard, and the nitrogen source is a chemical nitrogen source or a livestock and poultry manure nitrogen source.

5. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1 or 2, wherein the phosphorus source is calcium superphosphate, dipotassium hydrogen phosphate or potassium dihydrogen phosphate;

if calcium superphosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (4-5);

if dipotassium hydrogen phosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (6-7);

if monopotassium phosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (5-6).

6. The process for coproducing straw aerobic fermentation heat and fertilizer as claimed in claim 1 or 2, wherein the perishable material is bran, and the pH regulator is quicklime.

7. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1, wherein the fermentation container is externally provided with a heat insulation layer with a thickness of more than 10cm, and the heat insulation layer is a heat insulation material with a heat conductivity coefficient of less than 0.05W/(m.K).

8. The process of claim 7, wherein the fermentation vessel is a fermentation tank with a volume of 5L or more and the fermentation tank is made of an organic material with a thickness of 2mm or more;

if the system is an outdoor heat production system, the volume of the fermentation container is more than 30m³And the height of the fermentation tank is not less than 1.5m, and the fermentation tank is a container in a strip stack type, a pit type or a tank body.

9. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 8, wherein an insulating layer with a thickness of more than 10cm is arranged outside the fermentation tank of the outdoor heat production system, a PVC film is adhered to the outside of the insulating layer, and uncut straw is laid on the inside of the insulating layer.

10. The straw aerobic fermentation heat and fertilizer co-production process as claimed in claim 1, wherein a ventilation duct is laid at the bottom of the fermentation container, and natural ventilation is accelerated by reserving air holes around the ventilation duct and exposing part of the ventilation duct to the air.

Technical Field

The invention relates to the technical field of biomass thermal production, in particular to a straw aerobic fermentation heat and fertilizer co-production process.

Background

China is a big agricultural country, the yield of straws is high, the comprehensive utilization rate is low at present, and the treatment mode is mainly direct returning and burning. Wherein the mode of directly returning to the field can reduce soil quality, increases the crop plant diseases and insect pests risk, influences the growth of next season crop, and the mode of burning through the straw not only causes the waste of biomass resources, and the waste gas and the smoke and dust of production still seriously pollute the environment simultaneously. Because the density of the straws is small, and the economic cost of a centralized large-scale treatment mode is too high, the key point for treating the straw problem is to find a method for returning the straws to the field after the straws are recycled on site.

In order to improve the utilization rate of the straws, the method for carrying out aerobic fermentation on the straws to finally generate the organic fertilizer is a feasible method, and the aerobic fermentation is a solid waste treatment method for degrading organic matters through microorganisms under the action of oxygen. However, the common concern of aerobic fermentation is limited to the production of high quality fertilizer, and the utilization of waste heat in aerobic fermentation is neglected. Therefore, by using a fermentation heat production technology, the quality of the fertilizer can be improved to obtain a high-quality organic fertilizer, the utilization of heat energy can be realized, and the carbon emission is reduced.

The aerobic fermentation heat and fertilizer co-production technology of the straws has no mature process method in China at present, and the point needing breakthrough in the technology mainly has two aspects, namely, a heat preservation technology is adopted, and the larger the heat redundancy of the heat and fertilizer co-production technology is, the more the heat utilization is, the higher the requirement on the heat preservation capability is; on the other hand, the technology of long-term efficient and stable operation of fermentation is used, and maintaining high-temperature operation is the basis of heat extraction of compost, but the long-term efficient and stable operation of high temperature mainly depends on the design of composting processes, and the highest temperature and the high-temperature maintaining time of different composting processes are different, so that the problem that a composting process capable of relatively maintaining high temperature for a long time needs to be solved by technical personnel in the field is urgently needed.

Disclosure of Invention

In view of the above, the invention provides an aerobic fermentation process which takes straws as main raw materials and can continuously produce heat and high-quality organic fertilizer, aiming at the heat production requirement of aerobic fermentation, and can realize the co-production of heat and fertilizer in the process of the aerobic fermentation of the straws.

In order to achieve the purpose, the invention adopts the following technical scheme:

a straw aerobic fermentation heat and fertilizer co-production process comprises the following steps:

(1) straw pretreatment: pulverizing straw to 50-100kg/cm³；

(2) Fermentation construction: laying the pretreated straws at the bottom of a fermentation container, taking 20-40cm as a layer, fully mixing a nitrogen source, a phosphorus source, a pH regulator and water, then spreading the mixture on the surface of the straw layer, uniformly mixing the straws and all substances, and then sequentially spreading mixed liquid of perishable substances, mixed microbial inoculum and water on the surface;

(3) repeating the step (2) after the sowing is finished until the fermentation container is filled;

(4) preparing a fertilizer: taking out the fermented straws, naturally drying until the water content is below 30%, and crushing into granules;

the fermentation process is carried out by heat taking and cooling process, specifically, a water pipe is arranged at the center of the fermentation pile body, and the water pipe is arranged every 1m²Placing a water pipe with the length of more than 3m, driving the circulation power by a water pump to circulate, and controlling the water inlet temperature to be between 5 and 50 ℃. The invention transfers the redundant heat in the fermentation container to the circulating water to generate heat, and the heat extraction process is particularly important in the whole process and mainly aims at extracting heat.

Preferably, in the process for the co-production of the aerobic fermentation heat and fertilizer by the straws, the mixed microbial inoculum comprises 50% of EM (effective viable count) bacteria, 35-45% of lactobacillus, 3-5% of bacillus, 0.2-0.4% of burkholderia, 0.3-0.4% of Ralstonia, 0.2-0.5% of acinetobacter and 0.1-0.3% of acetic acid bacteria, and the effective viable count of the mixed microbial inoculum is more than 1 x 10¹⁰One per ml.

The microorganism is the basis of aerobic fermentation, and the microorganism carried by the fermentation raw material is difficult to achieve a good fermentation effect, so that a microbial inoculum is required to be added. The mixed microbial inoculum is rich in various microorganisms, and can quickly degrade organic matters in the raw materials, such as protein, cellulose, hemicellulose and the like, so that the fermentation process of the raw materials can be accelerated after the microbial inoculum is added, the heating process of the raw materials in the early stage can be accelerated by using the mixed microbial inoculum, the raw materials are quickly heated to reach the high temperature stage, and meanwhile, due to the existence of various microorganisms, the degradation effect of the raw materials in the high temperature stage is improved, so that the temperature in the stage is improved, the heat production capacity of aerobic fermentation is improved, in short, the addition of the mixed microbial inoculum can promote the fermentation, the heat production capacity of the raw materials is improved, and the fertilizer efficiency of the final fertilizer is improved.

Preferably, in the process for co-producing the aerobic fermentation heat and fertilizer by straw, the straw used for fermentation is prepared by an agricultural straw harvester or other cutting and kneading equipment, and the straw is crushed and then packaged by a packaging technology to form a straw square bag; or if the periphery of the fermentation area is the straw stacking area or the crop planting area, the straw can be directly used for fermentation after being rapidly crushed on site by a straw crusher.

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, the mass ratio of the straws, the nitrogen source, the phosphorus source, the pH regulator, the perishable substances and the water in the step (2) is 1000: (30-40): (40-70): (10-15): (10-30): 1000, and the ratio of the straws to the mixed microbial inoculum is 5 ml: (1-2) kg.

The proportion is determined through experiments, the fermentation process has the best effect in the proportion of the former materials, and the produced fertilizer has the highest fertilizer efficiency; the ratio of the straws to the microbial inoculum of the latter shows that the microbial inoculum can already exert the best effect under the ratio, and the fermentation effect of the raw materials cannot be greatly improved due to the extremely fast propagation of microorganisms and the addition of too much microbial inoculum, so that a ratio with excellent performance and lower cost is selected.

Preferably, in the process for the co-production of the straw aerobic fermentation heat and fertilizer, the EM is a common commercial microbial inoculum in the market; the lactobacillus can be selected from lactobacillus powder for fermentation, burkholderia, ralstonia and acinetobacter; the acetobacter is a common microorganism in soil and can be screened from the soil; the bacillus is commercially common bacillus powder.

Preferably, in the co-production process of the straw aerobic fermentation heat and fertilizer, the nitrogen source is added according to the carbon-nitrogen ratio of 10-30, and the nitrogen source is a chemical nitrogen source or a livestock and poultry manure nitrogen source.

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, the phosphorus source is calcium superphosphate, dipotassium hydrogen phosphate or potassium dihydrogen phosphate;

if calcium superphosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (4-5);

if dipotassium hydrogen phosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (6-7);

if monopotassium phosphate is used as a phosphorus source, the mass ratio of the straw to the phosphorus source is 100: (5-6).

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, the perishable substances are bran, and the pH regulator is quicklime.

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, a heat insulation layer with the thickness of more than 10cm is arranged outside the fermentation container, and the heat insulation layer is made of heat insulation materials with the heat conductivity coefficient of less than 0.05W/(m.K), such as polyurethane, rock wool, rubber-plastic plates, extruded plates or foam plates.

Preferably, in the co-production process of the straw aerobic fermentation heat and fertilizer, if the heat production system is a laboratory fermentation tank, the fermentation container is a fermentation tank with a volume of more than 5L, the fermentation tank is made of an organic material with a thickness of more than 2mm, and is in the shape of a vertical cylinder or a box body, and the heat insulation material and the thickness of the fermentation tank are jointly used as a heat insulation means.

Preferably, in the co-production process of the straw aerobic fermentation heat and fertilizer, if the process is an outdoor heat production system, the volume of the fermentation container is more than 30m³And the height of the fermentation tank is not less than 1.5m, and the fermentation tank is a container in a strip stack type, a pit type or a tank body.

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, a heat preservation layer with the thickness larger than 10cm is arranged outside the fermentation tank, a PVC film is pasted on the outer side of the heat preservation layer, and the straws which are not cut are laid on the inner side of the heat preservation layer.

Preferably, in the aerobic fermentation heat and fertilizer co-production process for straws, ventilation pipelines are laid at the bottom of the fermentation container, natural ventilation is accelerated by reserving air holes around the ventilation pipelines and exposing part of the ventilation pipelines to the air, corrugated pipes are laid at the bottom of the fermentation container, and natural ventilation is performed by reserving air holes around the corrugated pipes; and the fermentation temperature is adjusted.

Preferably, in the co-production process of the aerobic fermentation heat and fertilizer of the straws, the water pipe is arranged in the center of the fermentation pile body to take out the excess heat generated by fermentation for adjusting the temperature in the fermentation process, and the taken-out heat can be further utilized subsequently, and the utilization mode includes but is not limited to heating houses and greenhouses.

Specifically, natural ventilation is used for ventilation: laying 1.5-2m long corrugated pipe at the bottom of the fermentation tank, reserving air holes around the corrugated pipe, placing at the bottom of the fermentation pile, and placing at the amount of 1-2m²More than one is arranged on the bottom area of the bed;

preferably, in the process for the co-production of the aerobic fermentation heat and fertilizer of the straws, the fermentation construction process further comprises a material supplementing step, the material supplementing step is the same as the step (2), and if outdoor water taking in winter in the north is inconvenient, snow with equal mass can be adopted to replace water to dissolve a nitrogen source, a phosphorus source and a pH regulator.

In the first step of straw pretreatment, the outer surface of the straw is provided with a natural waxy layer which can affect fermentation, so that the straw is required to be crushed to expose the inside of the straw, in addition, the crushing treatment can increase the stacking density of the straw and improve the effective fermentation capacity of a fermentation body, so that the density of the straw is required to be maintained at 50kg/m³Above, but too high crushing degree can bring negative effects, firstly, too high stacking density can affect ventilation, aerobic fermentation needs the support of oxygen, so that too high crushing degree of straws can affect the fermentation process, secondly, raw material treatment cost can be increased, and the straw pretreatment process is more important;

the second step is a specific construction process, and the raw materials can be mixed as much as possible by adopting the operation process without using mechanical equipment. The proportion of fermentation raw materials is particularly important, firstly, the pH value influences microorganisms in the aerobic fermentation process, the change of a protein structure can be caused by the overhigh or overlow pH value, so that the activity of the microorganisms is reduced, bacteria are suitable for growing in a weak alkaline environment with the pH value of 7.5-8.5, fungi are suitable for growing in a weak acidic environment, and the pH range is generally adjusted to be 6-9; secondly, carbon-nitrogen ratio influences the carbon source and the nitrogen source of the microorganism in the aerobic fermentation process, which are important nutrients for the reproduction and metabolism of the microorganism. If the carbon source is too little, the microorganism lacks energy, the growth is inhibited, and the nitrogen element is volatilized in the form of ammonia gas to cause loss; the carbon source is too much, the synthesis of substances such as microbial protein, nucleic acid and the like is influenced, the growth and the propagation of the substances are inhibited, and the aerobic fermentation process is prolonged. Researches find that CN ratio is 10-30, which is beneficial to the decomposition of organic matters by microorganisms, but most of the substances do not meet the range, so that in the actual aerobic fermentation process, different raw materials are needed to adjust the balance between carbon and nitrogen required by the aerobic fermentation; thirdly, the water content influences microorganisms in the aerobic fermentation process, the life activities of the microorganisms need proper water, and the microorganisms cannot maintain normal life activities in an environment with too low water content, so that the metabolism is slow; too high water content causes insufficient oxygen supply inside the fermentation system, so that the growth of aerobic microorganisms is inhibited and even a large amount of aerobic microorganisms die, and foul odor is generated. A large number of researches show that the water content of the fermentation system is relatively suitable to be 50-70%.

According to the technical scheme, compared with the prior art, the invention discloses and provides a straw aerobic fermentation heat and fertilizer co-production process, which has the following beneficial effects:

(1) the invention mainly uses straws as fermentation raw materials to produce heat and fertilizer, compared with the similar process technology, the method has more diversified energy output modes and more comprehensive utilization modes of the straws, can increase the heat production of aerobic fermentation, is convenient for large-scale and mechanized construction, and has better fertilizer efficiency;

(2) the heat production quantity of the invention is between 2000-3000kJ/kg DM, while the heat production quantity of the common compost fermentation method is generally between 500-2500kJ/kg DM;

(3) the construction amount of the invention is 60m³Calculating that the total feeding construction time is 1.5 days, the construction amount of the common compost fermentation method is 3 days, and the construction period can be shortened by 50 percent;

(4) after the detection of the properties of the fertilizer, all indexes of the fertilizer meet the latest organic fertilizer standard NY-525-2021 of Ministry of agriculture.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram showing the dimensions of a fermenter according to an embodiment of the present invention;

FIG. 2 is a schematic view of an installation structure of a fermentation tank according to an embodiment of the present invention;

FIG. 3 is a graph showing the temperature change of a 5L fermenter;

FIG. 4 is a graph showing the temperature profile of a 30L fermenter (urea is a nitrogen source);

FIG. 5 is a graph showing the pH change in a 30L fermenter during fermentation;

FIG. 6 is a graph showing the change in conductivity during fermentation in a 30L fermenter;

FIG. 7 is a water content change curve of a 30L fermenter during fermentation;

FIG. 8 is a graph showing the GI variation of germination percentage during fermentation in a 30L fermenter;

FIG. 9 is a graph showing the temperature profile of a 30L fermenter (pig manure is nitrogen source);

FIG. 10 is a layout diagram of a temperature and oxygen sensor of a fermentation tank;

FIG. 11 is a view showing 60m in drawing³The change curves of the center of the fermentation tank and the ambient temperature;

FIG. 12 is a view showing 60m in the drawing³A fermentation tank oxygen content change curve;

FIG. 13 is an optical photograph showing the apparent form of the fermented material (A is a fresh sample taken out from a compost heap, and B is a treated organic fertilizer).

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The use volume is 5L, 5mm thick acrylic glass fermentation cylinder, and its internal height of jar is 20cm, and the diameter is 20cm, and the middle blind plate interlayer of arranging is used for accepting the filtration liquid, and the blind plate aperture is 5mm, and the board radius is 9cm, and the hole interval is 8mm, as shown in figure 1. The heat insulation material is a rubber-plastic plate with the thickness of 3.5cm, and is wound by three layers; the ventilation process uses an automatic aeration pump with the flow rate of 350-.

Pulverizing corn stalk to density of 64-70kg/cm³The average length of the particles is 2-4cm and the average width is 0.3-0.7 cm. Laying 100g of corn straws at the bottom of a fermentation tank, fully mixing 3-4g of urea, 4.0-5.0g of calcium superphosphate or 6.0-7.0g of dipotassium hydrogen phosphate or 5.0-6.0g of potassium dihydrogen phosphate, 1.0-1.5g of quicklime and 80ml of water, spreading the mixture on the surface of a straw layer, uniformly mixing the corn straws and the mixture, spreading 1-3g of bran on the surface of the mixture, spreading a mixed solution of 0.5ml of mixed microbial inoculum and 20ml of water on the surface of the mixture, repeating the steps after the spreading is finished, namely filling 100g of straws on the surface, and repeating the operation for 5 times until the fermentation tank is filled. The temperature profile of the fermentation process is shown in figure 3. As seen from the graph, short-term fermentation was completed in a small-scale fermenter.

Example 2

A30L, 5mm thick High Density Polyethylene (HDPE) fermenter was used, the tank was cylindrical-like, no blind plate, insulation, temperature sensing and ventilation were the same as in example 1.

Pulverizing corn stalk to density of 64-70kg/cm³The average length of the particles is 2-4cm and the average width is 0.3-0.7 cm. Laying 500g corn stalk at the bottom of fermentation tank, mixing 15-20g urea, 20.0-25.0g calcium superphosphate or 30-35g dipotassium hydrogen phosphate or 25-30g potassium dihydrogen phosphate, 5-7.5g quicklime and 400ml waterAnd mixing, spreading on the surface of a straw layer, uniformly mixing corn straws with the straw layer, spreading 5-15g of bran on the surface after uniformly mixing, spreading a mixed solution of 2.5ml of mixed microbial inoculum and 100ml of water on the surface, repeating the steps after spreading is finished, namely filling 500g of straws on the surface, and repeating the operation for 10 times until the fermentation tank is filled.

The temperature profile of the fermentation process is shown in figure 4. It is seen from the graph that the medium-term temperature performs well and has the property of continuous heat generation, and the heat generation capacity is calculated to be 2519.5kJ/kg DM. The pH change during the fermentation process is shown in figure 5, the change of the electric conductivity EC value is shown in figure 6, the change of the water content is shown in figure 7, the change of the germination percentage GI is shown in figure 8, the maize straws can gradually reach the rotten state from figure 5 to figure 8, and the indexes of the organic fertilizer measured according to the NY-525-2021 standard are shown in table 1.

Example 3

A30L, 5mm thick High Density Polyethylene (HDPE) fermenter was used, the tank was cylindrical-like, no blind plate, insulation, temperature sensing and ventilation were the same as in example 1.

Pulverizing corn stalk to density of 64-70kg/cm³The average length of the particles is 2-4cm and the average width is 0.3-0.7 cm. Laying 500g of corn straws at the bottom of a fermentation tank, fully mixing 300-400g of pig manure, 20.0-25.0g of calcium superphosphate or 30-35g of dipotassium hydrogen phosphate or 25-30g of monopotassium phosphate and 5-7.5g of quick lime with 400ml of water, spreading the mixture on the surface of a straw layer, uniformly mixing the corn straws and the mixture, spreading 5-15g of bran on the surface after uniformly mixing, spreading a mixed solution of 2.5ml of mixed microbial inoculum and 100ml of water on the surface, repeating the steps after the spreading is finished, namely filling 500g of straws on the surface, and repeating the operation for 10 times until the fermentation tank is filled.

The temperature curve of the fermentation process is shown in figure 9, and the middle temperature is shown to be good in performance and have continuous heat production performance, and the heat production capacity can be calculated to be 2347.6kJ/kg DM. The pH change during the fermentation process is shown in figure 5, the change of the electric conductivity EC value is shown in figure 6, the change of the water content is shown in figure 7, the change of the germination percentage GI is shown in figure 8, the maize straws can gradually reach the rotten state from figure 5 to figure 8, and the indexes of the organic fertilizer measured according to the NY-525-2021 standard are shown in table 1.

Example 4

The volume of use is 60m³The side wall of the outdoor strip-stack type fermentation tank adopts a specific gravity of 1.3g/cm³Polyvinyl chloride (PVC) film + volume weight of 80kg/m³The rock wool and the long straw quilt are insulated, the top of the rock wool and the long straw quilt is insulated by adopting a PVC film and a greenhouse cotton quilt, and a corrugated pipe with the length of 2m is laid below the rock wool and the long straw quilt and used as a natural ventilation pipe at the bottom of the greenhouse cotton quilt, and the arrangement positions of oxygen and temperature sensors are shown in an attached figure 10.

Laying two layers of uncut corn straws in a fermentation tank, wherein the thickness is 40cm, the using amount is 300-450kg, laying 15 bags of corn straw square bags weighing about 20kg in the fermentation tank, fully mixing 0.9-1.2kg of urea, 12.0-15.0kg of calcium superphosphate or 18-21kg of dipotassium hydrogen phosphate or 15.0-18kg of monopotassium phosphate and 0.3-0.45kg of quicklime with 240L of water, spreading the mixture on the surfaces of the straw layers, uniformly mixing the corn straws and the mixture, spreading 0.3-0.9kg of bran on the surfaces, spreading a mixed solution of 150ml of mixed microbial inoculum and 60L of water on the surfaces, repeating the steps after the spreading is finished, namely filling 15 bags of corn straw square bags on the surfaces, and repeating the operation for 30 times until the fermentation tank is filled.

The temperature curve of the fermentation process is shown in figure 11, and the change curve of oxygen content is shown in figure 12. As can be seen from the two figures, the process method of the embodiment realizes the heat production of the outdoor cold-region fermentation, and the change of the oxygen content indicates that the mass aerobic of the microorganisms in the system, and the mass propagation of the microorganisms and the degradation of organic matters are the root causes of the heat production.

In order to prevent the temperature from being overhigh, a water pipe with PPR and DN25 bent in a shape like a Chinese character 'ji' is designed in the fermentation pile, and the water pipe is arranged every 1m²The placing length of the water-saving filter is 3-4m, the circulating power is driven by a common self-priming water pump to circulate, the water inlet temperature is 10-15 ℃, and the water outlet temperature is above 40 ℃.

Feeding materials in 30 th and 45 th days of fermentation, because outdoor water taking is difficult in winter, snow is used for replacing water to dissolve a nitrogen source, a phosphorus source and a pH regulator, a small amount of water is used for dissolving the mixed microbial inoculum, the feeding amount is 1.2t each time, and the feeding materials are added in four layers in the same construction method.

For the fermented and decomposed organic fertilizer, the fertilizer efficiency test is carried out, the appearance of the prepared organic fertilizer is shown in the attached figure 13 according to the standard of NY-525-2021, and the organic fertilizer efficiency is shown in the table 1.

TABLE 1 physicochemical indices of the fermented organic fertilizers

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the scheme disclosed by the embodiment, the scheme corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.