Agricultural trough composting reaction system and control method therefor

Abstract

Agricultural trough composting reaction system, comprising: a fermentation tank; compost turner; aeration device; compost pile interior data monitoring module arranged to measure interior temperature,

Description

03 06 25 TECHNICAL FIELD The present invention relates to the technical field of trough-type aerobic composting, in particular to an agricultural trough composting reaction system and a control method therefor. BACKGROUND In order to reduce the impact on the environment in large-scale agricultural production, agricultural wastes such as poultry manure and straw are usually treated by materials, energy and substrates. In the above scheme, the substrates have a better harmless treatment capability on the one hand, and the cultivation substrates required for the agricultural production can be supplied on the other hand. At present, most of the substrate fermentation enterprises in China are based on tank aerobic fermentation, which has the advantages of large treatment capacity and low cost of regulation and management. However, in actual production, most of the compost pile turning and aeration operations are based on the experience of the operators, and lack automatic and accurate operation guidance, which easily leads to inaccurate judgment of substrate real-time fermentation in the production process, missing the optimal control time, and leading to the decline of the performance of fermented products. In the published patent, CN108752067A uses static aeration fermentation and forklift to turn over the tank for fermentation production. However, it lacks an automatic control system and mainly relies on the judgment of the operators, which cannot solve the problem of human judgment error. In addition, the above scheme does not consider the aeration temperature compensation pair; in view of the above problems, 03 06 25 the present invention provides an agricultural trough composting reaction system and a control method therefor to realize automatic control of fermentation process. SUMMARY An object of the present invention is to provide an agricultural trough composting reaction system and a control method therefor. In one aspect, the present invention provides a control method for the agricultural trough composting reaction system , comprising the following steps: Step SI: introducing to-be-fermented materials with a carbon-to-nitrogen ratio of 25-35:1 and a moisture content of 60%-75% into a fermentation tank, and fully and uniformly mixing the to-be-fermented materials by a compost turner by means of the turning and mixing action to form a compost pile; Step S2: measuring interior temperature data, CO2 concentration data, moisture content data and carbon-to-nitrogen ratio data of the compost pile after fermentation is performed for 24-48 hours; Step S3: performing data computation according to the measured data, and controlling the compost turner or an aeration device based on a computation result; wherein a compost pile turning operation is performed when the interior temperature of the compost pile exceeds a first temperature threshold; an aeration operation is performed when the interior temperature of the compost pile is lower than a second temperature threshold, wherein: when the interior temperature of the compost pile at the current moment Tt is between the second temperature threshold and the first temperature threshold, predicting whether the interior temperature of the compost pile at the next sampling moment Ti+1 is between the two thresholds according to a preset 03 06 25 computation model, and controlling the compost turner according to a predicted value; wherein the preset computation model is specifically as follows: if the concentration of CO2 in the compost pile at the current moment is Q, the environment temperature at the current moment is T, and the concentration of CO2 in the environment is Co; the upper surface area of the fermentation pile is S, and the total mass of the fermentation pile is m, with the unit being kg; the specific heat capacity is c, with the unit being J / (kg °C); the unit heat transfer coefficient of the to-be-fermented material is the air exchange rate is 8, the organic matter degradation and conversion coefficient is £, and the unit organic matter content of the to-be-fermented material is n, with the unit being g / kg; the amount of heat generated by degradation of unit organic matter of the to-be-fermented material is w, with the unit being kJ / g kg; according to the law of conservation of energy, the current heat value of the composting reaction system is the difference between the total heat released by the to-be-fermented material in the process of degradation from the initial moment 0 and the total heat released to the outside of the fermentation pile; assuming that all the heat transfer surfaces of the fermentation tank occur on the upper surface, then a discrete expression of a heat balance equation of the fermentation pile is obtained: mc^-^ = — Sp(Ti+± — T), where ni+1 is the organic matter content at the next moment, is the organic matter content at the current moment, and d is the sampling interval duration; through iterative algorithms and a kinetic equation of organic matter degradation, an expression of the interior temperature of the compost pile at the next w(ni+A-n0)-dSBYli-n(T i-T) sampling moment Ti+1 is obtained: Ti+1 =--------mc+ds^------- + T; assuming that the concentration of CO2 in the compost pile at the next sampling moment Ci+1 takes the maximum value at the previous three moments Cmax = Max{Ci_2> C^, Cj, and the concentration of CO2 in the environment 03 06 25 remains unchanged, then w(ni+1 — n0) =^(1 + d6)(Cmax — Co) + — Z}=o(Q — Co); a calculation formula of the interior temperature of the compost pile at the next moment Ti+1 is: _ y(l + - C„) + - Co) - dS^ - T) T‘+1 “ mc + dS0 +T when Ti+1 exceeds the first temperature threshold, sending, by a computation and control module, a first instruction to control the compost turner to perform a compost pile turning operation; Step S4: stopping the aeration operation and performing compost pile turning at intervals of 4-8 hours when the interior temperature data of the compost pile decreases to 40-45 °C and the moisture content data of the compost pile decreases to 50% or less after the to-be-fermented materials enter the fermentation tank for 10-15 days; and Step S5: continuously monitoring the moisture content data and carbon-to-nitrogen ratio data of the compost pile, and stopping fermentation when the moisture content data of the compost pile decreases to 40% or less and the carbon-to-nitrogen ratio data decreases to 20:1 or less. Further, in the step S3, when it is necessary to perform the compost pile turning operation in the case that the interior temperature of the compost pile exceeds the first temperature threshold, the aeration rate is controlled to be 0.2-0.6, with the unit being L / min kg, and the aeration operation duration is 10-30 min. In another aspect, the present invention further provides an agricultural trough composting reaction system having a computation and control module that executes the control method, characterized by comprising a fermentation tank, a compost turner, 03 06 25 and an aeration device, wherein the system further comprises a compost pile interior data monitoring module, an environmental data monitoring module and a wireless transmission module; wherein the compost pile interior data monitoring module is arranged to measure interior temperature data, CO2 concentration data, carbon-to-nitrogen ratio data and moisture content data of a compost pile at fixed time intervals, and the environmental data monitoring module is arranged to monitor temperature data and CO2 concentration data above the fermentation tank; the compost pile interior data monitoring module and the environmental data monitoring module are respectively connected with the computation and control module through the wireless transmission module; the computation and control module is connected with the compost turner and the aeration device, and is arranged to perform data computation, and to control the compost turner or the aeration device, according to the data measured by the two monitoring modules, wherein the said control comprises: when the interior temperature of the compost pile exceeds a first temperature threshold, the computation and control module sends a first instruction to control the compost turner to perform the compost pile turning operation; when the interior temperature of the compost pile is lower than a second temperature threshold, the computation and control module inside the compost pile sends a second instruction to control the aeration device to perform the aeration operation. Further, the aeration device comprises a plurality of air injection holes evenly distributed at the bottom of the fermentation tank, a gas heating device, and a gas booster pump; wherein when it is necessary to perform the aeration operation in the case that the 03 06 25 interior temperature of the compost pile is lower than the second temperature threshold, firstly, the gas heating device heats air to the second temperature threshold, and then the gas booster pump forces the heated air through the air injection holes to perform the aeration operation on the compost pile. Further, the fermentation tank is a rectangular tank with a fixed depth, the tank is matched with the compost turner in width such that the compost turner can move along an upper edge of the tank, and the bottom of the fermentation tank is also provided with a water guide groove; the compost turner is a chain-plate type fermentation compost turner. Compared with the prior art, the present invention has the beneficial effects that: 1, according to the present invention, the interior temperature data, CO2 concentration data, carbon-nitrogen ratio data and moisture content data of the compost pile are measured by the compost pile interior data monitoring module, and data computation and instruction control are performed according to the data measured by the monitoring modules to control the compost turner or the aeration device, so that the automatic control of the trough fermentation process is realized, the likelihood of misjudgment caused by human judgment is greatly reduced, the fermentation process is more complete, and the production efficiency of substrate fermentation is improved; 2, according to the present invention, when the compost pile turning control is performed, the operation needs are judged according to the compost pile parameters predicted in advance at the next sampling moment, so as to avoid the problem of overheating and decay caused by excessive temperature in the compost pile; at the same time, during the aeration operation, the effect of accelerating the fermentation 03 06 25 process and shortening the fermentation period can be achieved by preheating introduced gas. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic composition diagram of an agricultural trough composting reaction system according to the present invention. FIG. 2 is a flowchart of a control method for an agricultural trough composting reaction system according to the present invention. DETAILED DESCRIPTION In order to make the objects, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making inventive labor, belong to the scope of protection of the present invention. Embodiment 1 As shown in FIG. 1, an agricultural trough composting reaction system in this embodiment includes: a fermentation tank, a compost turner, an aeration device, a compost pile interior data monitoring module, an environmental data monitoring module, a wireless transmission module, and a computation and control module. The compost pile interior data monitoring module is arranged to measure interior temperature data, CO2 concentration data, carbon-to-nitrogen ratio data and moisture 03 06 25 content data of a compost pile at fixed time intervals, and the environmental data monitoring module is arranged to monitor temperature data and CO2 concentration data above the fermentation tank. The compost pile interior data monitoring module and the environmental data monitoring module are respectively connected with the computation and control module through the wireless transmission module. The computation and control module is connected with the compost turner and the aeration device, and is arranged to perform data computation and to control the compost turner or the aeration device according to the data measured by the two monitoring modules. It should be noted that the computation and control module controls the compost turner or the aeration device according to a data computation result after to-be-fermented materials enter the fermentation tank for 24-48 hours. When the interior temperature of the compost pile exceeds a first temperature threshold, the computation and control module sends a first instruction to control the compost turner to perform a compost pile turning operation, wherein the compost turner is a chain-plate type fermentation compost turner. It should be noted that the chain-plate type fermentation compost turner is suitable for organic fertilisers. A chain-driven and rolling-supported chain plate mechanism is adopted, so that the compost turner has small anti-throwing resistance, saves electricity and energy, and is suitable for deep trough operation; the walking system, on the fermentation tank, of the compost turner adopts frequency conversion speed regulation, so that the compost turner has good adaptability to different materials, and 03 06 25 is stable and high efficiency in compost pile turning. The fermentation tank is a rectangular tank with a fixed depth, and the tank is matched with the compost turner in width such that the compost turner can move along the upper edge of the tank, and the bottom of the fermentation tank is also provided with a water guide groove. When the interior temperature of the compost pile is lower than a second temperature threshold, the computation and control module inside the compost pile sends a second instruction to control the aeration device to perform an aeration operation; in the process of aerobic composting, temperature is an important factor affecting microbial activities, the composting process may go through a process from a temperature rising stage to a high temperature stage to a temperature drop stage. During the composting process, the rate of change of the temperature of the compost pile will be affected by the conditions such as ventilation and composting equipment, the appropriate temperature for fermentation of the composting materials is 55-60 °C. Therefore, the value range of the first temperature threshold is set to 65-70 °C, and the value range of the second temperature threshold is set to 45-55 °C; the value range of the fixed time interval is 10-30 min. The aeration device includes a plurality of air injection holes evenly distributed at the bottom of the fermentation tank, a gas heating device, and a gas booster pump. It should be noted that the purpose of micro-aerobic fermentation is to reduce volatile substances and odor in materials, kill parasite eggs and pathogenic microorganisms, and achieve the purpose of harmlessness. In addition, through high-temperature fermentation treatment, the moisture content of organic materials is reduced, and the organic materials are decomposed and mineralised to release nutrients such as N, P and K, and at the same time, the properties of organic materials become loose and dispersed. Firstly, on one hand, the compost turner is utilised to thoroughly mix the 03 06 25 fermented materials through the turning and mixing action, which allows for rapid evaporation of moisture and displacement of the materials. On the other hand, the aeration system installed at the bottom of the fermentation tank supplies oxygen through forced ventilation, thus creating favorable conditions for the decomposition of microorganisms while also releasing moisture and decomposition gases. In the present invention, when it is necessary to perform the aeration operation in the case that the interior temperature of the compost pile is lower than the second temperature threshold, firstly, the gas heating device heats air to the second temperature threshold, and then the gas booster pump forces the heated air through the air injection holes to perform the aeration operation on the compost pile. By preheating the introduced air, the fermentation process can be accelerated, resulting in a shortened fermentation cycle. Controlling the compost turner or the aeration device further includes: predicting whether the interior temperature of the compost pile at the next sampling moment exceeds the first temperature threshold according to a preset computation model when the interior temperature of the compost pile at the current moment is between the second temperature threshold and the first temperature threshold; and sending, by the computation and control module, the first instruction to control the compost turner to perform the compost pile turning operation if it is calculated that the interior temperature of the compost pile at the next sampling moment exceeds the first temperature threshold. It should be noted that the computation model used to determine the interior temperature of the compost pile at the next sampling moment is: according to the law of conservation of energy, the current heat value of the composting reaction system is the difference between the total heat released by the to-be-fermented material in the 03 06 25 process of degradation from the initial moment 0 and the total heat released to the outside of the fermentation pile. Assuming that all the heat transfer surfaces of the fermentation tank occur on the upper surface, thereby obtaining a discrete expression of the heat balance equation of the fermentation pile, and an expression of the interior temperature of the compost pile at the next sampling moment is obtained by means of iterative algorithms and the kinetic equation of organic matter degradation; assuming that the concentration of CO2 in the compost pile at the next sampling moment takes the maximum value at the previous three moments, and the concentration of CO2 in the environment remains unchanged, then a calculation formula of the interior temperature of the compost pile at the next moment can be obtained, and when the interior of the compost pile at the next moment exceeds the first temperature threshold, the computation and control module sends a first instruction to control the compost turner to perform a compost pile turning operation. Performing data computation and instruction control according to the data measured by the two monitoring modules, and controlling the compost turner or the aeration device further includes: controlling, by the computation and control module, the compost turner according to the interior temperature data and moisture content data of the compost pile after the to-be-fermented materials enter the fermentation tank for 10-15 days. When the interior temperature data of the compost pile decreases to 40-45 °C and the moisture content data of the compost pile decreases to 50% or less, the aeration operation is stopped, and the compost turner is controlled to perform compost pile turning at intervals of 4-8 hours. 03 06 25 The fermentation is stopped when the moisture content data of the compost pile decreases to 40% or less and the carbon-to-nitrogen ratio data decreases to 20:1 or less. Embodiment 2 In another aspect, the present invention provides a control method for an agricultural trough composting reaction system, including the following steps: Step SI: introducing to-be-fermented materials with a carbon-to-nitrogen ratio of 25-35:1 and a moisture content of 60%-75% into a fermentation tank, and fully and uniformly mixing the to-be-fermented materials by a compost turner by means of the turning and mixing action to form a compost pile; Step S2: measuring interior temperature data, CO2 concentration data, moisture content data and carbon-to-nitrogen ratio data of the compost pile after fermentation is performed for 24-48 hours; Step S3: performing data computation according to the measured data, and controlling the compost turner or the aeration device based on a computation result; wherein A compost pile turning operation is performed when the interior temperature of the compost pile exceeds a first temperature threshold; an aeration operation is performed when the interior temperature of the compost pile is lower than a second temperature threshold; Step S4: stopping the aeration operation and performing compost pile turning at intervals of 4-8 hours when the interior temperature data of the compost pile decreases to 40-45 °C and the moisture content data of the compost pile decreases to 50% or less after the to-be-fermented materials enter the fermentation tank for 10-15 days; and Step S5: continuously monitoring the moisture content data and carbon-to-nitrogen ratio data of the compost pile, and stopping fermentation when the moisture content 03 06 25 data of the compost pile decreases to 40% or less and the carbon-to-nitrogen ratio data decreases to 20:1 or less. It should be noted that when the interior temperature of the compost pile at the current moment Tt is between the second temperature threshold and the first temperature threshold, predicting whether the interior temperature of the compost pile at the next sampling moment Ti+1 is between the two thresholds according to a preset computation model, and controlling the compost turner according to the predicted value. It should be noted that the preset computation model is specifically as follows: if the concentration of CO2 in the compost pile at the current moment is Q, the environment temperature at the current moment is T, and the concentration of CO2 in the environment is Co; the upper surface area of the fermentation pile is S, and the total mass of the fermentation pile is m, with the unit being kg; the specific heat capacity is c, with the unit being J / (kg °C); the unit heat transfer coefficient of the to-be-fermented material is the air exchange rate is 6, the organic matter degradation and conversion coefficient is £, and the unit organic matter content of the to-be-fermented material is n, with the unit being g / kg; the amount of heat generated by degradation of unit organic matter of the to-be-fermented material is w, with the unit being kJ / g kg; according to the law of conservation of energy, the current heat value of the composting reaction system is the difference between the total heat released by the to-be-fermented material in the process of degradation from the initial moment 0 and the total heat released to the outside of the fermentation pile; assuming that all the heat transfer surfaces of the fermentation tank occur on the upper surface, then a discrete expression of a heat balance equation of the fermentation pile is obtained: me T‘+^ T‘ = w n‘+^ n‘ — (Ti+1 — T) , where ni+1 is the organic 03 06 25 matter content at the next moment, is the organic matter content at the current moment, and d is the sampling interval duration; through iterative algorithms and the kinetic equation of organic matter degradation, an expression of the interior temperature of the compost pile at the next sampling w(ni+A —n0)—dSB X\=n(Tt) moment Ti+1 is obtained: Ti+1 =-------------------- + T\ assuming that the concentration of CO2 in the compost pile at the next sampling moment Ci+1 takes the maximum value Cmax = Max{Ci_2, C^, Cj at the previous three moments, and the concentration of CO2 in the environment remains unchanged, then w(ni+1 - n0) = j(l + d8\Cmax - + - Co); a calculation formula of the interior temperature of the compost pile at the next moment Ti+1 is: _ 7 (1 + d8^Cmax ~ Co) + - Co) - dSp ^(Tj - T) Ti+1 - mc + dSp + T when Ti+1 exceeds the first temperature threshold, the computation and control module sends a first instruction to control the compost turner to perform a compost pile turning operation. It should be noted that when it is necessary to perform the compost pile turning operation in the case that the interior temperature of the compost pile exceeds the first temperature threshold, the aeration rate is controlled to be 0.2-0.6, with the unit being L / minkg, and the aeration operation duration is 10-30 min. The specific embodiments described above, the objects, technical solutions and advantageous effects of the present invention are further explained in detail, it should be understood that the foregoing description is only specific embodiments of the present invention and is not intended to limit the scope of the present invention, and that all modifications, equivalents, improvements, and the like within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

16 04 251. A control method for the agricultural trough composting reaction system , characterized by comprising the following steps:Step SI: introducing to-be-fermented materials with a carbon-to-nitrogen ratio of 25-35:1 and a moisture content of 60%-75% into a fermentation tank, and fully and uniformly mixing the to-be-fermented materials by a compost turner by means of the turning and mixing action to form a compost pile;Step S2: measuring interior temperature data, CO2 concentration data, moisture content data and carbon-to-nitrogen ratio data of the compost pile after fermentation is performed for 24-48 hours;Step S3: performing data computation according to the measured data, and controlling the compost turner or an aeration device based on a computation result; whereina compost pile turning operation is performed when the interior temperature of the compost pile exceeds a first temperature threshold;an aeration operation is performed when the interior temperature of the compost pile is lower than a second temperature threshold, wherein:when the interior temperature of the compost pile at the current moment Tt is between the second temperature threshold and the first temperature threshold, predicting whether the interior temperature of the compost pile at the next sampling moment Ti+1 is between the two thresholds according to a preset computation model, and controlling the compost turner according to a predicted value; whereinthe preset computation model is specifically as follows:if the concentration of CO2 in the compost pile at the current moment is Q, the environment temperature at the current moment is T, and the concentration of16 04 25CO2 in the environment is Coi the upper surface area of the fermentation pile is S, and the total mass of the fermentation pile is m, with the unit being kg; the specific heat capacity is c, with the unit being J / (kg °C); the unit heat transfer coefficient of the to-be-fermented material is the air exchange rate is 8, the organic matter degradation and conversion coefficient is £, and the unit organic matter content of the to-be-fermented material is n, with the unit being g / kg; the amount of heat generated by degradation of unit organic matter of the to-be-fermented material is w, with the unit being kJ / g kg; according to the law of conservation of energy, the current heat value of the composting reaction system is the difference between the total heat released by the to-be-fermented material in the process of degradation from the initial moment 0 and the total heat released to the outside of the fermentation pile;assuming that all the heat transfer surfaces of the fermentation tank occur on the upper surface, then a discrete expression of a heat balance equation of the fermentation pile is obtained: mc^-^ = — Sp(Ti+± — T), where ni+1 isthe organic matter content at the next moment, is the organic matter content at the current moment, and d is the sampling interval duration;through iterative algorithms and a kinetic equation of organic matter degradation, an expression of the interior temperature of the compost pile at the next w(ni+A-n0)-dS B Yli=n(T i-t)sampling moment Ti+1 is obtained: Ti+1=-------mc+ds^------- + T;assuming that the concentration of CO2 in the compost pile at the next sampling moment Ci+1 takes the maximum value at the previous three moments Cmax = Max{Ci_2> C^, Cj, and the concentration of CO2 in the environment remains unchanged, then w(ni+1 — n0) =^(1 + d8)(Cmax — Co) + —Co);a calculation formula of the interior temperature of the compost pile at the next moment Ti+1 is:16 04 25_ 7 (1 + M)(Cmax - Co) + ^Sj-=o(C,- - Co) - MP ^(Tj - T)T,+1 ” mc + dS / 3 +Twhen Ti+1 exceeds the first temperature threshold, sending, by a computation and control module, a first instruction to control the compost turner to perform a compost pile turning operation;Step S4: stopping the aeration operation and performing compost pile turning at intervals of 4-8 hours when the interior temperature data of the compost pile decreases to 40-45 °C and the moisture content data of the compost pile decreases to 50% or less after the to-be-fermented materials enter the fermentation tank for 10-15 days; andStep S5: continuously monitoring the moisture content data and carbon-to-nitrogen ratio data of the compost pile, and stopping fermentation when the moisture content data of the compost pile decreases to 40% or less and the carbon-to-nitrogen ratio data decreases to 20:1 or less.

2. The control method for the agricultural trough composting reaction system according to claim 1, wherein in the step S3, when it is necessary to perform the compost pile turning operation in the case that the interior temperature of the compost pile exceeds the first temperature threshold, the aeration rate is controlled to be 0.2-0.6, with the unit being L / min kg, and the aeration operation duration is 10-30 min.

3. An agricultural trough composting reaction system having a computation and control module that executes the control method according to claim 1 or claim 2, characterized by comprising a fermentation tank, a compost turner, and an aeration device, wherein the system further comprises a compost pile interior data monitoring module, an environmental data monitoring module and a wireless transmission16 04 25module; whereinthe compost pile interior data monitoring module is arranged to measure interior temperature data, CO2 concentration data, carbon-to-nitrogen ratio data and moisture content data of a compost pile at fixed time intervals, and the environmental data monitoring module is arranged to monitor temperature data and CO2 concentration data above the fermentation tank;the compost pile interior data monitoring module and the environmental data monitoring module are respectively connected with the computation and control module through the wireless transmission module;the computation and control module is connected with the compost turner and the aeration device, and is arranged to perform data computation, and to control the compost turner or the aeration device, according to the data measured by the two monitoring modules, wherein the said control comprises:when the interior temperature of the compost pile exceeds a first temperature threshold, the computation and control module sends a first instruction to control the compost turner to perform the compost pile turning operation;when the interior temperature of the compost pile is lower than a second temperature threshold, the computation and control module inside the compost pile sends a second instruction to control the aeration device to perform the aeration operation.

4. The agricultural trough composting reaction system according to claim 3, characterized in that the aeration device comprises a plurality of air injection holes evenly distributed at the bottom of the fermentation tank, a gas heating device, and a gas booster pump; whereinwhen it is necessary to perform the aeration operation in the case that the interior temperature of the compost pile is lower than the second temperaturethreshold, firstly, the gas heating device heats air to the second temperature threshold, and then the gas booster pump forces the heated air through the air injection holes to perform the aeration operation on the compost pile.

5. The agricultural trough composting reaction system according to claim 3 or claim 4, characterized in that the fermentation tank is a rectangular tank with a fixed depth, the tank is matched with the compost turner in width such that the compost turner can move along an upper edge of the tank, and the bottom of the fermentation tank is also provided with a water guide groove;the compost turner is a chain-plate type fermentation compost turner.16 04 25

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