Drying method of high-water-content organic solid waste

Abstract

The invention relates to the technical field of high-water-content organic solid waste drying, in particular to a high-water-content organic solid waste drying method. According to the technical scheme, by means of the target organic matter, a carbon source can be provided for the target strain, and moisture diffusion channels between the solid waste blocks formed by the high-water-content organic solid waste can be supported, so that unbound water surrounded by the multiple solid waste blocks is diffused outwards from the moisture diffusion channels; organic matters in the high-water-content organic solid waste can be degraded and the porosity and the specific surface area of the high-water-content organic solid waste can be increased by virtue of the target strain; the temperature in the sunlight shed and the temperature of the target mixture in the drying process do not exceed 50 DEG C, so that good survival conditions of the target strains can be guaranteed, and the risk of dust explosion caused by dust concentration increase in the later drying period due to introduction of the target organic matter can be reduced. And the target mixture receives solar radiation, is continuously turned and is driven by the fan, so that the high-water-content organic solid waste is dried.

Description

Technical Field

[0001] The invention relates to the technical field of measuring organic solid waste with high water content, and in particular to a drying method for organic solid waste with high water content. Background Art

[0002] High-water content organic solid waste refers to organic solid waste with high water content generated in the production and living process, including municipal waste, printing and dyeing waste, river waste, livestock manure, wine lees, oil sludge, kitchen waste, etc. High-water content organic solid waste has the following characteristics: 1) It is highly polluting, easy to rot and deteriorate, breed mosquitoes and pathogens, and pose a great threat to environmental protection and public health; 2) There is a large gap, with annual production usually measured in tens of millions or even billions of tons. The existing disposal capacity is seriously insufficient, the disposal technology is backward, and some areas still mainly use landfill.

[0003] In the related technologies, the drying process of organic solid waste with high water content generally has the common problems of low efficiency and high energy consumption. The reason is that organic solid waste with high water content is prone to shrinkage and agglomeration during the drying process, which causes the pore structure to be locked and the resistance of internal water (i.e., unbound water) to diffuse and evaporate outward increases sharply.

[0004] Therefore, there is an urgent need for a drying method for high-water-content organic solid waste to solve the above technical problems. Summary of the invention

[0005] The invention provides a method for drying organic solid waste with high water content, which can promote the water diffusion of the organic solid waste with high water content to improve the drying effect of the organic solid waste with high water content.

[0006] The embodiment of the present invention provides a method for drying high-water-content organic solid waste, comprising:

[0007] Mixing the high-water-content organic solid waste to be dried, target organic matter and target bacterial species to obtain a target mixture; wherein the target organic matter is used to provide a carbon source for the target bacterial species, and the target bacterial species is used to degrade organic matter in the high-water-content organic solid waste and increase the porosity and specific surface area of ​​the high-water-content organic solid waste;

[0008] The target mixture is laid in a sun shed to receive sunlight radiation; wherein a plurality of fans are arranged in the sun shed, a gas inlet is arranged at one end of the sun shed, and a gas outlet is arranged at the other end;

[0009] Using the fan to drive the evaporated water of the target mixture to be discharged from the gas outlet;

[0010] The target mixture laid in the sun shed is continuously turned over during the drying process to ensure uniform contact between the materials in the target mixture; wherein the target organic matter is also used to support the water diffusion channel between the solid waste clumps formed by the high-water content organic solid waste, so that the unbound water surrounded by the multiple solid waste clumps diffuses outward from the water diffusion channel;

[0011] The high-water content organic solid waste is dried by allowing the target mixture to receive sunlight radiation, continuously turning the pile and using the fan to drive it, so that the moisture content of the high-water content organic solid waste is less than 40%; wherein the temperature in the sun shed and the temperature of the target mixture during the drying process do not exceed 50°C.

[0012] It can be seen from the above scheme that the drying method of high-water-content organic solid waste provided by the present invention can not only provide a carbon source for the target bacteria, but also support the moisture diffusion channel between the solid waste clumps formed by the high-water-content organic solid waste, so that the unbound water surrounded by multiple solid waste clumps can diffuse outward from the moisture diffusion channel; the target bacteria can degrade the organic matter in the high-water-content organic solid waste and increase the porosity and specific surface area of ​​the high-water-content organic solid waste, so as to improve the microscopic morphology of the solid waste and improve the permeability and permeability of the solid waste; and the temperature in the sun shed and the temperature of the target mixture during the drying process do not exceed 50°C, which can not only ensure the better survival conditions of the target bacteria, but also reduce the risk of dust explosion caused by the increase in dust concentration in the later stage of drying due to the introduction of the target organic matter; in this way, the drying of the high-water-content organic solid waste is achieved by allowing the target mixture to receive sunlight radiation, continuously turning the pile and using the fan to drive it, so that the moisture content of the high-water-content organic solid waste is less than 40%. Therefore, the above technical solution effectively solves the problem of low drying efficiency caused by shrinkage, agglomeration and pore structure closure of high-water-content organic solid waste during the drying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A schematic flow chart of a method for drying high-water-content organic solid waste provided in an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the structure of a drying system for high-water-content organic solid waste provided by an embodiment of the present invention;

[0016] Figure 3A schematic diagram of the shrinkage and agglomeration of solid waste agglomerates and how to avoid shrinkage and agglomeration provided in an embodiment of the present invention;

[0017] Figure 4 A schematic diagram of thermal conductivity calculation provided in an embodiment of the present invention.

[0018] Reference numerals:

[0019] 1-sunroom; 2-fan; 3-gas inlet; 4-gas outlet; 5-target mixture; 6-controller. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 and Figure 2 One embodiment of the present invention provides a method for drying high-water-content organic solid waste, comprising:

[0022] Step S1, mixing the high-water content organic solid waste to be dried, the target organic matter and the target bacterial species to obtain a target mixture 5; wherein the target organic matter is used to provide a carbon source for the target bacterial species, and the target bacterial species is used to degrade organic matter in the high-water content organic solid waste and increase the porosity and specific surface area of ​​the high-water content organic solid waste;

[0023] Step S2, laying the target mixture 5 in the sun shed 1 to receive sunlight radiation; wherein a plurality of fans 2 are arranged in the sun shed 1, a gas inlet 3 is arranged at one end of the sun shed 1, and a gas outlet 4 is arranged at the other end;

[0024] Step S3, using the fan 2 to drive the evaporated water of the target mixture 5 to be discharged from the gas outlet 4;

[0025] Step S4, continuously turning the target mixture 5 laid in the sun shed 1 during the drying process to ensure that the materials in the target mixture 5 are in uniform contact; wherein the target organic matter is also used to support the water diffusion channel between the solid waste clumps formed by the high-water content organic solid waste, so that the unbound water surrounded by the multiple solid waste clumps diffuses outward from the water diffusion channel;

[0026] The high-water content organic solid waste is dried by allowing the target mixture 5 to receive sunlight radiation, continuously turning the pile and using the fan 2 to drive it, so that the moisture content of the high-water content organic solid waste is less than 40%; wherein the temperature in the sun shed 1 and the temperature of the target mixture 5 during the drying process do not exceed 50°C.

[0027] In this embodiment, the target organic matter can not only provide a carbon source for the target bacteria, but also support the water diffusion channel between the solid waste clumps formed by the high-water content organic solid waste (see Figure 3 , when the target organic matter is not added and the compost is not turned continuously, the pores collapse and shrink and agglomerate; when the target organic matter is added and the compost is turned continuously, no pore collapse and shrinkage and agglomeration occur), so that the unbound water surrounded by multiple solid waste clumps diffuses outward from the water diffusion channel; the organic matter in the high-water content organic solid waste can be degraded and the porosity and specific surface area of ​​the high-water content organic solid waste can be increased by means of the target bacteria, so as to improve the microscopic morphology of the solid waste and improve the permeability and permeability of the solid waste; and the temperature in the sun shed 1 and the temperature of the target mixture 5 during the drying process do not exceed 50°C, which can not only ensure the better survival conditions of the target bacteria, but also reduce the risk of dust explosion caused by the increase in dust concentration in the later stage of drying due to the introduction of the target organic matter; in this way, the high-water content organic solid waste is dried by making the target mixture 5 receive sunlight radiation, continuously turning the compost and using the fan 2 to make the water content of the high-water content organic solid waste less than 40%. Therefore, the above technical solution effectively solves the problem of low drying efficiency caused by shrinkage, agglomeration and pore structure closure of high-water-content organic solid waste during the drying process.

[0028] It should be noted that the continuous compost turning operation in the embodiment of the present invention can better ensure the uniformity of each substance in the target mixture 5, so that the target organic matter can better support the water diffusion channels between the solid waste clumps formed by the high-water content organic solid waste. On the contrary, the fermentation heat production activity of the target strain in the embodiment of the present invention is relatively large compared to the way in which continuous compost turning forms a large number of water diffusion channels, and the former has a negligible effect on drying. Moreover, the continuous compost turning operation can also adjust the parameters such as the moisture content, pH value, C / N ratio in the target mixture 5 to optimize the growth environment of the target strain.

[0029] In some embodiments, the moisture content of the high-water content organic solid waste is greater than 80%, which is not specifically limited in this embodiment of the present invention.

[0030] In some embodiments, the target organic matter includes at least one of straw and leaves.

[0031] In some embodiments, the target bacterial species include at least one of photosynthetic bacteria, yeast, lactic acid bacteria, Pseudomonas, Bacillus and actinomycetes.

[0032] In some embodiments, the mass ratio of the target organic matter to the dry basis of the high water content organic solid waste is 8-12%, which is not specifically limited in this embodiment of the present invention.

[0033] In some embodiments, the mass ratio of the target bacteria to the dry basis of the high-water-content organic solid waste is 2-5%, which is not specifically limited in this embodiment of the present invention.

[0034] In one embodiment of the present invention, the setting position of the fan 2 in the sun shed 1 is determined by the following method:

[0035] Grid the sun shed 1 in Fluent software;

[0036] Selecting a target mathematical model in Fluent software; wherein the target mathematical model includes a flow model, a component model and a heat transfer model;

[0037] Determine the boundary conditions in Fluent software and assign values ​​to the boundary conditions; wherein the boundary conditions include the density, specific heat, thermal conductivity, viscosity and laying thickness of the high-water content organic solid waste and the sunlight radiation intensity, wind speed, temperature and humidity in the sun shed 1;

[0038] The drying process of organic solid waste with high water content is numerically simulated to obtain the flow field, humidity field and temperature field in the sun shed 1;

[0039] Based on the flow field, humidity field and temperature field in the sun shed 1 , a first setting position of the fan 2 in the sun shed 1 is determined.

[0040] In this embodiment, the temperature field, humidity field and flow field are optimized by adjusting the first setting position of the fan 2 in the sun shed 1, so that the drying efficiency of high-water organic solid waste is improved by strengthening the water mass transfer process. At the same time, by modeling the physicochemical changes, heat transfer and water migration of high-water organic solid waste (i.e., flow model, component model and heat transfer model), the physical mechanism of the drying process can be better understood, thereby optimizing the design of the sun shed 1 and improving the drying efficiency.

[0041] It can be understood that based on the flow field in the sun shed 1, it can be seen which areas are stagnant areas, so a fan 2 can be set in the stagnant areas to drive the airflow movement in the stagnant areas; based on the humidity field in the sun shed 1, it can be seen which areas are drying dead corners, so a fan 2 can be set in the drying dead corners to drive the airflow to the drying dead corners; based on the temperature field in the sun shed 1, the temperature distribution can be seen, so a fan 2 can be set in the area with higher temperature to drive the airflow to the area with lower temperature. In this way, the setting position of the fan 2 in the sun shed 1 can be optimized.

[0042] like Figure 4 As shown, in one embodiment of the present invention, the thermal conductivity of high water content organic solid waste is determined by the following method:

[0043] The cylindrical cylinder is divided into two spaces, the upper and lower spaces, and the lower space of the cylindrical cylinder is filled with high-water content organic solid waste, and the upper space of the cylindrical cylinder is an air space;

[0044] A heating rod is inserted into the center of the cylindrical tube to heat the organic solid waste with high water content and the air by using the heating rod; wherein the heating rod is arranged in the upper space and the lower space;

[0045] Inserting a first temperature sensor into a non-center of the lower space, inserting a second temperature sensor into a non-center of the upper space, and inserting a third temperature sensor into the center of the high-water-content organic solid waste to monitor the temperature of the heating rod; wherein the distance from the first temperature sensor to the heating rod is equal to the distance from the second temperature sensor to the heating rod;

[0046] The thermal conductivity of high water content organic solid waste is determined by the following formula:

[0047]

[0048] Wherein, λs is the thermal conductivity, ha is the height of the upper space, hs is the height of the lower space, t1 is the temperature detected by the first temperature sensor, t2 is the temperature detected by the second temperature sensor, and t3 is the temperature detected by the third temperature sensor.

[0049] It should be noted that the above formula assumes that heat is only conducted from the cylindrical surface and the temperature only changes with the radius r. It is a one-dimensional stable temperature field heat conduction. According to Fourier's law of stable heat conduction, the heat conduction rate of a certain microelement (the amount of heat conducted per unit time) is proportional to the normal temperature gradient of the isothermal surface of the microelement and the heat conduction area of ​​the microelement.

[0050] In one embodiment of the present invention, a plurality of dryers (not shown in the figure) are further provided in the sun shed 1, and the dryers are used to dry high water content organic solid waste;

[0051] Drying of high-water-content organic solid waste is achieved by allowing the target mixture 5 to receive sunlight radiation, continuously turning the pile, using the fan 2 to drive it, and using the dryer to dry it.

[0052] In this embodiment, by arranging a plurality of drying machines in the sun shed 1, the drying efficiency of high water content organic solid waste can be further improved.

[0053] In one embodiment of the present invention, the second setting position of the dryer in the sun shed 1 is determined based on the humidity field and the temperature field in the sun shed 1 .

[0054] In this embodiment, the temperature field and humidity field are optimized by adjusting the second setting position of the dryer in the sun shed 1, so that the drying efficiency of high-water organic solid waste is improved by strengthening the water mass transfer process. At the same time, by modeling the physicochemical changes, heat transfer and water migration of high-water organic solid waste (i.e., component model and heat transfer model), the physical mechanism of the drying process can be better understood, thereby optimizing the design of the sun shed 1 and improving the drying efficiency.

[0055] It is understandable that based on the humidity field in the sun shed 1, it is possible to see which areas are drying dead corners, so that a dryer can be set in the drying dead corners to dry the moisture in the drying dead corners; based on the temperature field in the sun shed 1, the temperature distribution can be seen, so that a dryer can be set in a low temperature area to transfer the temperature to the low temperature area. In this way, the second setting position of the dryer in the sun shed 1 can be optimized.

[0056] In one embodiment of the present invention, the method further includes:

[0057] Based on the real-time parameters of the high-water content organic solid waste and the sun shed 1 (which can be obtained by the first sensor component and the second sensor component respectively, and the first sensor component and the second sensor component are not shown in the figure), the operating speed of the fan 2 and the frequency of continuous compost turning (which can be achieved by a compost turning machine, which is not shown in the figure) are controlled (the control logic can be achieved by the controller 6); wherein the real-time parameters of the high-water content organic solid waste include the density, specific heat, thermal conductivity, viscosity and laying thickness of the high-water content organic solid waste, and the real-time parameters of the sun shed 1 include the sunlight radiation intensity, wind speed, temperature and humidity in the sun shed 1.

[0058] In this embodiment, since the real-time parameters of high-water-content organic solid waste and the sun shed 1 are constantly changing during the actual engineering application process, in order to continuously maintain a stable and efficient drying efficiency, it is possible to consider effectively monitoring and dynamically adjusting the entire drying process, that is, with the help of the controller 6, the first sensor assembly and the second sensor assembly, the operating speed of the fan 2 and the turning frequency of the pile turning machine can be controlled to better achieve efficient drying.

[0059] It can be understood that the first sensor component includes, for example, a dynamic torque sensor (for measuring viscosity), a density sensor, a heat flow sensor (for measuring specific heat), a temperature sensor (for measuring thermal conductivity, see above), etc., and the second sensor component includes, for example, a temperature sensor, a humidity sensor, a wind speed sensor, a radiation sensor, etc.

[0060] In one embodiment of the present invention, the controller 6 specifically controls the operating speed of the fan 2 and the turning frequency of the compost turning machine in the following manner:

[0061] Constructing a training sample set; wherein the training sample set includes the density, specific heat, thermal conductivity, viscosity and laying thickness of the high-water content organic solid waste as input training samples, the sunlight radiation intensity, wind speed, temperature and humidity in the sun shed 1, and the solid waste characteristic index as output training samples, and the solid waste characteristic index is used to characterize the material properties of the high-water content organic solid waste;

[0062] Inputting the constructed training sample set into the preset neural network model to train the neural network model and obtain a dynamic adjustment model;

[0063] The real-time parameters of high-water organic solid waste and sun shed 1 are input into the dynamic adjustment model to obtain the solid waste characteristic index at the current moment;

[0064] Based on the solid waste characteristic index at the current moment, the operating speed of the fan 2 and the turning frequency of the compost turning machine are controlled.

[0065] In this embodiment, end-to-end training and learning can be quickly achieved through machine learning. There is no need to consider the correlation between the various intermediate parameters, but only needs to update the weights of the neural network model based on a large amount of known data to obtain a more accurate output result. Therefore, this method can quickly establish a mapping relationship between input (i.e., parameters of high-water-content organic solid waste and sun shed 1) and output (i.e., solid waste characteristic index).

[0066] In one embodiment of the present invention, the controller 6 performs the following operations when controlling the operating speed of the fan 2 and the turning frequency of the compost turning machine based on the solid waste characteristic index at the current moment:

[0067] If SI = 0, fan 2 and the rake machine are controlled to start;

[0068] If 0<SI≤25, the operating speed of fan 2 is controlled to be 100% and the turning frequency of the compost turning machine is controlled to be 30 times / hour;

[0069] If 25<SI≤75, the operating speed of fan 2 is controlled to 80% and the turning frequency of the compost turning machine is controlled to 20 times / hour;

[0070] If 75<SI≤125, the speed of fan 2 is controlled to be 60% and the frequency of turning the compost by the rake turner is controlled to be 15 times / hour;

[0071] If 125<SI≤175, the speed of fan 2 is controlled to be 40% and the frequency of turning the compost by the rake turner is controlled to be 10 times / hour;

[0072] If 175<SI≤225, the speed of fan 2 is controlled to be 20% and the frequency of turning the compost by the rake turner is controlled to be 5 times / hour;

[0073] If 225<SI, fan 2 and the rake machine are controlled to stop running;

[0074] Among them, SI is the solid waste characteristic index at the current moment.

[0075] In this embodiment, by setting a solid waste characteristic index (SI) as a judgment indicator of the controller 6, compared with multiple input parameters (such as multiple parameters of high-water content organic solid waste and the sun shed 1), the former can more quickly realize the control of the operating speed of the fan 2 and the turning frequency of the compost turning machine.

[0076] It should be noted that, in the present invention, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0077] Finally, it should be noted that the above is only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for drying high-water content organic solid waste, characterized in that: include: Mixing the high-water-content organic solid waste to be dried, target organic matter and target bacterial species to obtain a target mixture; wherein the target organic matter is used to provide a carbon source for the target bacterial species, and the target bacterial species is used to degrade organic matter in the high-water-content organic solid waste and increase the porosity and specific surface area of ​​the high-water-content organic solid waste; The target mixture is laid in a sun shed to receive sunlight radiation; wherein a plurality of fans are arranged in the sun shed, a gas inlet is arranged at one end of the sun shed, and a gas outlet is arranged at the other end; Using the fan to drive the evaporated water of the target mixture to be discharged from the gas outlet; The target mixture laid in the sun shed is continuously turned over during the drying process to ensure uniform contact between the materials in the target mixture; wherein the target organic matter is also used to support the water diffusion channel between the solid waste clumps formed by the high-water content organic solid waste, so that the unbound water surrounded by the multiple solid waste clumps diffuses outward from the water diffusion channel; The high-water content organic solid waste is dried by allowing the target mixture to receive sunlight radiation, continuously turning the pile and using the fan to drive it, so that the moisture content of the high-water content organic solid waste is less than 40%; wherein the temperature in the sun shed and the temperature of the target mixture during the drying process do not exceed 50°C.

2. The method for drying high-water-content organic solid waste according to claim 1, characterized in that: The water content of the high-water content organic solid waste is greater than 80%.

3. The method for drying high-water content organic solid waste according to claim 1, characterized in that: The target organic matter includes at least one of straw and leaves.

4. The method for drying high-water content organic solid waste according to claim 1, characterized in that: The target bacterial species include at least one of photosynthetic bacteria, yeast, lactic acid bacteria, pseudomonas, bacillus and actinomycetes.

5. The method for drying high-water-content organic solid waste according to claim 1, characterized in that: The mass ratio of the target organic matter to the dry basis of the high-water-content organic solid waste is 8-12%.

6. The method for drying high-water-content organic solid waste according to claim 1, characterized in that: The mass ratio of the target bacteria to the dry basis of the high-water-content organic solid waste is 2-5%.

7. The method for drying high-water-content organic solid waste according to any one of claims 1 to 6, characterized in that: The fan is positioned in the sun shed in the following manner: Meshing the sun shed in Fluent software; Selecting a target mathematical model in the Fluent software; wherein the target mathematical model includes a flow model, a component model and a heat transfer model; Determining boundary conditions in the Fluent software and assigning values ​​to the boundary conditions; wherein the boundary conditions include the density, specific heat, thermal conductivity, viscosity and laying thickness of the high-water content organic solid waste and the sunlight radiation intensity, wind speed, temperature and humidity in the sun shed; Numerical simulation is performed on the drying process of the organic solid waste with high water content to obtain the flow field, humidity field and temperature field in the sun shed; Based on the flow field, humidity field and temperature field in the sun shed, a first setting position of the fan in the sun shed is determined.

8. The method for drying high-water-content organic solid waste according to claim 7, characterized in that: The sun shed is also provided with a plurality of dryers, which are used to dry the organic solid waste with high water content; The drying of the high-water-content organic solid waste is achieved by allowing the target mixture to receive sunlight radiation, continuously turning the pile, driving it with the fan, and drying it with the dryer.

9. The method for drying high-water-content organic solid waste according to claim 8, characterized in that: The second setting position of the dryer in the sun shed is determined based on the humidity field and the temperature field in the sun shed.

10. The method for drying high-water-content organic solid waste according to claim 7, characterized in that: Also includes: Based on the real-time parameters of the high-water content organic solid waste and the sun shed, the operating speed of the fan and the frequency of continuous turning of the pile are controlled; wherein the real-time parameters of the high-water content organic solid waste include the density, specific heat, thermal conductivity, viscosity and laying thickness of the high-water content organic solid waste, and the real-time parameters of the sun shed include the sunlight radiation intensity, wind speed, temperature and humidity in the sun shed.

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