Organic biomass aerobic fermentation oxygen supply control method

Abstract

The invention discloses an organic biomass aerobic fermentation oxygen supply control method based on multi-sensor fusion and state observation, and the method comprises the steps: arranging a temperature sensor, a humidity sensor, a pressure sensor, a flow sensor and a weighing device in a fermentation device, and collecting inlet and outlet air parameters and material temperature and mass in real time; the method comprises the following steps: dynamically calculating the moisture evaporation amount based on humid air science and mass conservation, estimating the fermentation heat release amount in combination with a heat balance model, fusing multi-source data through a Kalman filter, dynamically correcting the mass of organic matters and the state quantity of the heat release amount, and realizing accurate estimation of oxygen consumption without an oxygen probe; according to the method, through a residual driving weight adjustment mechanism, measured value correction is enhanced in the fermentation temperature rising period to avoid insufficient oxygen supply, model trust is enhanced in the stationary period to inhibit excessive aeration, closed-loop aeration control is achieved, the scheme gives consideration to energy efficiency, stability and suitability, and oxygen supply accuracy and fermentation efficiency are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic solid waste resource processing, and particularly relates to an oxygen supply control method for aerobic fermentation of organic biomass. BACKGROUND

[0002] The aerobic fermentation compost is a mainstream technology for realizing the resource and harmless treatment of organic solid waste, and its essence relies on the metabolic activity of aerobic microorganisms under sufficient oxygen. The accuracy of oxygen supply directly determines the fermentation efficiency, energy consumption level and quality of the final product.

[0003] The current oxygen supply control of aerobic fermentation mainly relies on two types of technologies. One is to directly monitor the oxygen concentration of the pile body by using electrochemical or optical oxygen sensors. However, the working conditions of aerobic fermentation are extremely harsh, and it is long-term in a high-temperature (60-80℃) and high-humidity (>95% RH) environment, and is accompanied by high-concentration corrosive gases such as hydrogen sulfide and ammonia. In this environment, the oxygen probe generally has problems such as serious drift of the measurement signal, poisoning of the probe, and rapid reduction of the service life. Frequent calibration and replacement not only significantly increase the maintenance cost, but also lead to unreliable monitoring data, and it is impossible to use for real-time monitoring. The other is indirect calculation by gas analysis, which generally uses infrared analyzers or mass spectrometers to monitor the oxygen concentration difference between the inlet and outlet, and combines the conventional oxygen consumption rate (OUR), carbon dioxide generation rate (CER) and respiratory entropy (RQ) to calculate the oxygen consumption by mass balance. However, the equipment cost is high, the gas pretreatment (dust removal and moisture removal) requirement is extremely high, and it is difficult to carry out gas analysis in the initial stage of aerobic fermentation in order to ensure the temperature rise of the material.

[0004] Therefore, there is a lack of technical path to realize low-cost and high-robustness precise oxygen supply control. SUMMARY

[0005] To solve the above technical problems, the application discards the traditional idea of directly measuring the oxygen component, and creatively proposes a method of indirect oxygen measurement and control of ventilation volume based on multi-parameter fusion and dynamic heat balance model. The core idea of the application is to realize the accurate oxygen supply control without oxygen probe by accurately measuring the heat release of fermentation in real time and dynamically backstepping the instantaneous oxygen consumption of microorganisms, and to realize the accurate oxygen supply control without oxygen probe. At the same time, since there are many material parameters, the model error caused by time-varying drift may affect the ventilation volume, so the Kalman filter is introduced to construct the state observer, and the residual error between the real-time measurement value and the model prediction value is used to dynamically correct the key state quantity.

[0006] The application provides an oxygen supply control method for aerobic fermentation of organic biomass, which comprises the following steps:

[0007] S1: The temperature measuring device and the stirring device are arranged inside the fermentation device to make the temperature distribution in the fermentation device uniform; the fermentation device is provided with a weighing device;

[0008] S2: Before the fermentation starts, the total mass of the fermentation material is determined, the fermentation material is divided into three components of water, inorganic matter and organic matter, the water content and the organic matter content of the material are measured, and the initial masses of the three components in the material are calculated; the initial state covariance matrix P0, the measurement noise matrix Q and the process noise matrix R are determined based on the Kalman filtering method;

[0009] S3: Each Δt time is calculated as a time step, and the parameters are monitored once in the time step, including the temperature, humidity, volume flow and pressure of the inlet and outlet of the fermentation device, the average temperature of the material in the fermentation device, and the total mass of the material; the water evaporation amount E in the Δt time is calculated according to the temperature, humidity and flow of the inlet and outlet air;

[0010] S4: The masses of the three components of water, inorganic matter and organic matter in the fermentation material at time t are respectively:

[0011] Water mass: m (w,t) ;

[0012] Inorganic matter mass: m (n,t) ;

[0013] Organic matter mass: m (y,t) ;

[0014] Total mass of material in the fermentation device: m t ;

[0015] The mass of inorganic matter is constant during the fermentation process;

[0016] Each kilogram of organic matter decomposed in the fermentation process generates α kg of water, and α is related to the type of material;

[0017] The masses of the three components in each time step, the masses of the three components at time t and at time t-1, α and E exist the following relationships:

[0018] m t = m (w,t) + m (n,t) + m (y,t)

[0019] m t-1 = m (w,t-1) + m (n,t-1) + m (y,t-1)

[0020] m (n,t) = m (n,t-1) = m (n,0)

[0021]

[0022] m (w,t) = m (w,t-1) + a(m (y,t-1) - m (y,t) )-E

[0023] S5: calculating the average specific heat capacity of the material in each time step, the average specific heat capacity of the material being equal to the average value of the specific heat capacities of the components weighted by mass; based on the heat balance model, calculating the heat release of the aerobic fermentation in each time step; the heat release of the aerobic fermentation being equal to the sum of the sensible heat change of the material, the external heat dissipation and the increase of the import and export air enthalpy value;

[0024] S6: based on the Kalman filtering method, determining a plurality of state parameters, calculating the predicted value of the state parameters in each time step; updating the prior covariance matrix, updating the Kalman gain matrix after calculating the residual, and finally obtaining the optimal estimation and updating the state covariance matrix;

[0025] S7: calculating the oxygen consumption: calculating the current oxygen equivalent heat according to the organic matter consumption ratio, calculating the aerobic fermentation heat release based on the state parameters in the optimal estimation in S6, and dividing the oxygen equivalent heat to calculate the oxygen consumption;

[0026] S8: calculating the theoretical ventilation according to the oxygen consumption, and calculating the actual ventilation considering a certain margin, and controlling the fan operation according to the actual ventilation.

[0027] The technical solution of the application also includes the following technical features:

[0028] Preferably, in an embodiment of the application, the initial state covariance matrix P0, the measurement noise matrix Q and the process noise matrix R are determined as follows:

[0029]

[0030] β is the measurement error of organic matter.

[0031] Preferably, in an embodiment of the application, in S3, the monitoring parameters of the import and export are measured once in each time step, and the water evaporation E in the calculation time is calculated.

[0032] The air temperature T ain of the import;

[0033] The air temperature T aout of the export;

[0034] The air humidity RH in of the import;

[0035] The air humidity RH out of the export;

[0036] Inlet air volume flow rate Q vin ;

[0037] Outlet air volume flow rate Q vout ;

[0038] Inlet air pressure P in ;

[0039] Outlet air pressure P out ;

[0040] Inlet air saturated vapor pressure P satin ;

[0041]

[0042] Outlet air saturated vapor pressure P satout ;

[0043]

[0044] The water evaporation amount E in the time Δt is calculated as follows:

[0045]

[0046] The intermediate parameters are substituted to obtain E.

[0047] Preferably, in an embodiment of the present application, in S4, the value range of α for sludge is 0.3-0.6, and the value of α for other materials can be measured by experiment, i.e., the value of α for non-sludge materials is measured by experiment or obtained by simulation.

[0048] Preferably, in an embodiment of the present application, in S5, the average value of the specific heat capacity of each component at time t is calculated as the average specific heat capacity C (p,t) of the material by mass weighting, and the average specific heat capacity of the material is:

[0049]

[0050] C (p,w) : the specific heat capacity of water, taking the value of 4.18 kJ / (kg·K);

[0051] C (p,y) : the specific heat capacity of organic matter, measured;

[0052] C (p,n) : the specific heat capacity of inorganic matter, measured.

[0053] Preferably, in an embodiment of the present application, in S5, the expression of the heat balance model is constructed as:

[0054] Q f,t = mt ×C (p,t) ×T t -m t-1 ×C (p,t-1) ×T t-1 +Q loss +(H out -H in )

[0055] Q f,t : heat release of aerobic fermentation of the heat balance model;

[0056] T t : material temperature at time t;

[0057] T t-1 : material temperature at time t-1;

[0058] Q loss : heat dissipation of the fermentation device;

[0059] H in : enthalpy value carried by the inlet air;

[0060] H out : enthalpy value carried by the outlet air;

[0061] C (p,t) : weighted specific heat capacity of the fermentation material at time t;

[0062] C (p,t-1) : weighted specific heat capacity of the fermentation material at time t-1.

[0063] Preferably, in an embodiment of the present application, in S6, the state parameters are selected as the organic matter mass m y,t-1,true and the heat release Q f,t-1,true of aerobic fermentation at time t-1; the material temperature and the material mass change are selected as the observation parameters; and the optimal estimation of the time step state parameters at time t-1 is:

[0064] x t-1 = [Q f,t-1,true , m y,t-1,true ] T

[0065] The observation vector is:

[0066] z = [T t , Δm t ] T = [T t , m t - m t-1 ] T

[0067] Δm t = m t-m t-1 ;

[0068] The observation matrix is:

[0069]

[0070] Based on the linear extrapolation of the change at the previous time t-1, the organic matter mass m of the material is calculated. y,t,pred Aerobic fermentation releases heat

[0071] Q f,t,pred The predicted value;

[0072] x t,pred =[Q f,t,pred ,m y,t,pred ] T =[Q f,t-1,true +Q f,t-1 -Q f,t-2 ,m y,t-1,true +m (y,t-1) -m (y,t-2) ] T

[0073] In the initial Δt time or the second Δt time period after the system starts up, there is no initial data. By assuming that the data is 0, the filter will converge within the continuous iteration time steps.

[0074] Assume m y,t,pred and Q f,t,pred Given the data, and T t and Δm t For unknown values; substitute into the intermediate quantity formula and use the calculation unit to find T. t and Δm t The approximate solution, i.e.: approximate solution T t and Δm t The solution residual is <0.001, at which point T t and Δm t The approximate solution is the predicted value of the parameter, denoted as T. t,pred and Δm t,pred ,Right now:

[0075] Compensation residual y t calculate:

[0076] y t =[T t -T t,pred ,Δm t -Δm t,pred ] T

[0077] Update the prior covariance matrix:

[0078] Pt|t-1 = P t + Q

[0079] Update the Kalman gain matrix:

[0080] K t = P t|t-1 H T (HP t|t-1 H T + R) -1

[0081] Compute the optimal estimate within the current step:

[0082] x t = x t,pred + K t y t

[0083] That is:

[0084] [Q f,t,true , m y,t,true ] T = [Q f,t,pred , m y,t,pred ] T + K t y t

[0085] Update the covariance:

[0086] P t = (1 - K t H)P t|t-1

[0087] Q f,t,true is the heat release of aerobic fermentation described in S7.

[0088] Preferably, in an embodiment of the present application, in S7, Q loss is the heat dissipation of the fermentation device to the outside:

[0089] Q loss = 0.5k x A x (T t-1 - T aint ) x At / 1000

[0090] k: the heat dissipation coefficient of the fermentation device to the outside convection;

[0091] A: the contact area of the fermentation tank with air;

[0092] T t-1 : the material temperature at time t-1;

[0093] T aint : the air temperature at time t.

[0094] Preferably, in an embodiment of the present application, in S5, the enthalpy H carried by the outlet air out :

[0095] H out = m dryout × ((1.006 × T aout + D out × (2501 + 1.86 × T aout )

[0096] Outlet air mass

[0097]

[0098] Outlet air humidity D out :

[0099]

[0100] The cumulative output air molar quantity n in Δt time out :

[0101]

[0102] R is the gas constant;

[0103] Outlet water vapor volume fraction

[0104]

[0105] Outlet air saturated vapor pressure P satout :

[0106]

[0107] The enthalpy H carried by the inlet air in :

[0108] H in = m dryin × ((1.006 × T ain + D in × (2501 + 1.86 × T ain ) The cumulative input dry air mass m in Δt time dryin :

[0109]

[0110] Inlet air humidity D in :

[0111]

[0112] Molar amount of cumulative input air in Δt time of import in :

[0113]

[0114] Import water vapor volume fraction

[0115]

[0116] Import air saturated vapor pressure P satin :

[0117]

[0118] Preferably, in an embodiment of the present application, in S7, oxygen heat equivalent

[0119]

[0120] m (y,0) : initial moment of organic matter mass;

[0121] Oxygen consumption The calculation formula is:

[0122]

[0123] Preferably, in an embodiment of the present application, in S8, the actual control air volume Q v_in is used to perform aeration, and the margin coefficient ε is 1.1-1.3, that is, Q v_in = εQ air ; the theoretical air volume Q air :

[0124]

[0125] ρ air is the air density.

[0126] Preferably, in an embodiment of the present application, the fermentation device is provided with a heat preservation cover; the organic matter is pretreated, and aerobic microbial strains are added; the aerobic microbial strains include bacillus and actinomycetes.

[0127] Additional aspects and advantages of the application will be described in part below, will become apparent from the following description, or will be learned by practice of the application.

[0128] The present application is suitable for the industrialized aerobic fermentation process of sludge, livestock and poultry manure, kitchen waste and the like, and the control of the aerobic fermentation aeration of organic biomass based on a heat balance model, and the present application proposes an aerobic fermentation oxygen supply control method and system for multiple types of organic biomass and energy reduction and emission reduction, which accurately calculates the aerobic heat and oxygen consumption by dynamically adjusting the oxygen heat equivalent, and matches the aeration intensity;

[0129] The core advantage of the present application lies in that by fusing temperature, humidity, volume flow and mass sensors, combining a heat balance model and the principle of mass conservation, dynamically calculating the water evaporation, organic matter consumption and fermentation heat release, the present application realizes the precise oxygen supply control without an oxygen probe, effectively solves the problem of easy failure of the traditional oxygen sensor in a high temperature and high humidity environment, and significantly reduces the equipment cost; meanwhile, the present application dynamically corrects the key state quantity through the self-adaptive mechanism based on the Kalman filter residual error driving, and increases the robustness; in addition, the present application can effectively save energy and reduce emissions, avoid insufficient oxygen supply in the fermentation warming period, and inhibit excessive aeration in the stable period. BRIEF DESCRIPTION OF DRAWINGS

[0130] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0131] Figure 1 The material monitoring temperature curve of the aerobic fermentation oxygen supply control method of the organic biomass of the present application;

[0132] Figure 2 The ventilation quantity calculation curve comparison diagram of the aerobic fermentation oxygen supply control method of the organic biomass of the present application. DETAILED DESCRIPTION

[0133] The specific embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present application, and are not limiting to the present application.

[0134] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for description purposes, and cannot be understood as indicating or implying relative importance.

[0135] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0136] In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0137] An organic biomass aerobic fermentation oxygen supply control method, comprising the following steps: S1: arranging temperature measuring device and stirring device inside the fermentation device to make the temperature distribution in the fermentation device uniform; the fermentation device is provided with a weighing device;

[0138] S2: before fermentation starts, determining the total mass of the fermentation material, decomposing the fermentation material into three components of water, inorganic matter and organic matter, measuring the water content and organic matter content of the material, and calculating the initial mass of the three components in the material. Based on the Kalman filtering method, the initial state covariance matrix P0, the measurement noise matrix Q and the process noise matrix R are determined.

[0139] S3: each Δt time is calculated as a time step, and the parameters are monitored once in the time step, including the temperature, humidity and volume flow and pressure of the inlet and outlet of the fermentation device, the average temperature of the material in the fermentation device, and the total mass of the material; the water evaporation amount E in Δt time is calculated according to the temperature, humidity and flow of the inlet and outlet air;

[0140] S4: the masses of the three components of water, inorganic matter and organic matter in the fermentation material at time t are respectively:

[0141] Water mass: m (w,t) ;

[0142] Inorganic matter mass: m (n,t) ;

[0143] Organic matter mass: m (y,t) ;

[0144] Total mass of the material in the fermentation device: m t ;

[0145] The mass of inorganic matter is constant during the fermentation process;

[0146] Each kilogram of organic matter decomposed in the fermentation process of the material will generate α kg of water, and α is related to the type of the material;

[0147] The masses of the three components at each time step, t, t-1, α, and E are related as follows:

[0148] m t =m (w,t) +m (n,t) +m (y,t)

[0149] m t-1 =m (w,t-1) +m (n,t-1) +m (y,t-1)

[0150] m (n,t) =m (n,t-1) =m (n,0)

[0151]

[0152] m (w,t) =m (w,t-1) +α(m (y,t-1) -m (y,t) )-E

[0153] S5: Calculate the average specific heat capacity of the material at each time step. The average specific heat capacity of the material is equal to the mass-weighted average of the specific heat capacities of each component. Based on the heat balance model, calculate the heat release of aerobic fermentation at each time step. The heat release of aerobic fermentation is equal to the sum of the change in sensible heat of the material, the heat dissipation to the outside, and the increase in the enthalpy of the inlet and outlet air.

[0154] S6: Based on the Kalman filter method, several state parameters are determined, and the predicted values ​​of the state parameters within each time step are calculated. The prior covariance matrix is ​​updated, the residuals are calculated, and the Kalman gain matrix is ​​updated. Finally, the optimal estimate is obtained, and the state covariance matrix is ​​updated.

[0155] S7: Calculate oxygen consumption: Calculate the current oxygen heat equivalent based on the proportion of organic matter consumed. Using the optimal estimated state parameters in S6, calculate the heat release of aerobic fermentation and divide it by the oxygen heat equivalent to calculate the oxygen consumption.

[0156] S8: Calculate the theoretical ventilation volume based on oxygen consumption, and calculate the actual ventilation volume with a certain margin, and control the operation of the fan based on the actual ventilation volume.

[0157] Example 1: Measure the inlet and outlet monitoring parameters every Δt time interval;

[0158] Imported air temperature T ain (Unit: °C)

[0159] The air temperature at the outlet, T aout (Unit: °C)

[0160] Inlet air humidity RH in ;

[0161] Outlet air humidity RH out ;

[0162] Inlet air volume flow rate Q vin , unit m 3 / s;

[0163] Outlet air volume flow rate Q vout , unit m 3 / s;

[0164] Inlet air pressure P in , unit Pa;

[0165] Outlet air pressure P out , unit Pa;

[0166] Inlet air molar amount n accumulated in Δt time in :

[0167]

[0168] Inlet air saturated vapor pressure P satin , unit Pa:

[0169]

[0170] Inlet air actual vapor pressure P vin , unit Pa:

[0171]

[0172] Inlet water vapor volume fraction

[0173]

[0174] Inlet water vapor mass unit kg:

[0175]

[0176] Molar mass of oxygen, 0.018 kg / mol.

[0177] Dry air mass m accumulated in Δt time dryin , unit kg:

[0178]

[0179] wherein 0.02897 is the molar mass of dry air, unit kg / mol;

[0180] Import air moisture content D in , unit kg / kg dry :

[0181]

[0182] Further simplification:

[0183]

[0184] The enthalpy H carried by the import air in Δt time in :

[0185] H in = m dryin × ((1.006 × T ain + D in × (2501 + 1.86 × T ain ) The cumulative output air molar quantity n in Δt time out :

[0186]

[0187] Outlet air saturated vapor pressure P satout , unit Pa:

[0188]

[0189] Outlet air actual vapor pressure P vout , unit Pa:

[0190]

[0191] Outlet water vapor volume fraction

[0192]

[0193] Outlet water vapor mass unit kg:

[0194]

[0195] The cumulative output dry air mass m in Δt time dryout , unit kg:

[0196]

[0197] Outlet air moisture content D out , unit kg / kg dry :

[0198]

[0199] H = m x (Hin + Hout) out :

[0200] H out = m dryout x ((1.006 x T aout + D out x (2501 + 1.86 x T aout )

[0201] E = m x (Hin - Hout)

[0202]

[0203] Substitute Simplify:

[0204]

[0205] Combine, extract, and simplify:

[0206]

[0207] Substitute and simplify:

[0208]

[0209] Substitute and simplify:

[0210]

[0211] Substitute and simplify:

[0212]

[0213] Further:

[0214]

[0215] Substitute the above parameters to calculate E;

[0216] The technical solution has the following technical features:

[0217] The present application collects temperature, humidity, flow rate, pressure, weight, and multiple-point temperature, establishes a wet air science and mass balance model, and obtains the water evaporation amount;

[0218] The material is divided into three components: water, degradable organic matter, and inorganic matter. The mass of each component is updated using a given coupling, and the multi-component specific heat capacity is calculated over time;

[0219] The heat of fermentation is calculated by heat balance, and the oxygen consumption is converted using the oxygen heat equivalent that changes with the degradation progress;

[0220] The theoretical air volume is corrected to the actual control volume by safety margin and humidity / water content constraints;

[0221] The intermittent aeration logic is updated in real time to track fast in the dynamic stage and save energy in the steady state stage.

[0222] Specifically, in an embodiment of the present application, in S2: alpha is obtained by experimental determination or simulation calculation;

[0223] The fermentation device is provided with a heat preservation cover; the organic matter is pretreated, and aerobic microbial strains are added;

[0224] The aerobic microbial strains include bacillus and actinomycetes;

[0225] The ratio of water generated per kilogram of organic matter decomposition in the material fermentation process is obtained by experimental determination or simulation calculation and is used as an input parameter for regulating water content and ventilation strategy, combined with real-time monitoring of temperature and humidity data for dynamic adjustment; The fermentation device is provided with a heat preservation cover outside, which can reduce heat loss when the environmental temperature is low, and cooperate with ventilation cooling when needed to realize the balanced control of the heap temperature; After the material pretreatment, aerobic bacteria such as bacillus and actinomycetes are added, these bacteria groups show strong heat resistance and degradation capacity in the high temperature stage, and can quickly decompose cellulose, hemicellulose and protein substances, cooperate with the zoned oxygen supply system to keep the local area always at an appropriate oxygen level, thereby improving the overall decomposition rate; Through the above-mentioned mode, not only the coordinated regulation of water generation and heat change in the fermentation process is realized, but also the material water content is maintained in the appropriate range, and a stable aerobic environment is maintained throughout the fermentation process, which significantly improves the organic matter degradation efficiency and composting uniformity, and finally obtains an organic fertilizer product with loose structure, stable and harmless and rich in humus.

[0226] Specifically, in an embodiment of the present application, the heat generation calculation method;

[0227] S1: The fermentation material is divided into three components of water, inorganic matter and organic matter, the total mass m0 of the material, the organic matter content VS of the material and the water content M of the material are recorded at the initial moment of fermentation, and the initial temperature T0 in the fermentation tank.

[0228] The initial organic matter mass m of the material (y,0) , unit: kg:

[0229] m (y,0) = m0 x (1-M) x VS

[0230] The initial water mass m of the material (w,0) , unit: kg:

[0231] m (w,0) = m0 x M

[0232] Material inorganic matter content m (n,0) , unit kg:

[0233] m (n,0) = m0- m (w,0) -m (y,0) S2: every kg of organic matter decomposition will generate a kg of water during the material fermentation process, in this embodiment, a = 0.33 kg / kg vs Every time interval At (s) is monitored once, the last time monitoring parameter subscript is t-1, and the current time monitoring parameter subscript is t;

[0234] m (w,t) = m (w,t-1) + a (m (y,t-1) -m (y,t) )-E

[0235]

[0236] The inorganic matter content of the material remains constant:

[0237] m (n,t) = m (n,t-1) = m (n,0) S3: dynamic calculation of multi-component specific heat capacity, the average value weighted by the specific heat capacity mass of each component is taken as the average specific heat capacity C of the material (p,t) (kJ / kg), the average specific heat capacity of the material at time t is:

[0238]

[0239] Or

[0240]

[0241] C (p,w) : specific heat capacity of water, 4.18 kJ / (kg·K) in this embodiment

[0242] C (p,y) : specific heat capacity of organic matter, 1.5 kJ / (kg·K) in this embodiment

[0243] C (p,n) : specific heat capacity of inorganic matter, 0.8 kJ / (kg·K) in this embodiment

[0244] S4: establish a heat balance model;

[0245] Q f,t = m t × C (p,t) × T t -m t-1 × C (p,t-1) × T t-1 + Q loss +(Hout -H in )

[0246] Q f,t : heat release of aerobic fermentation, kJ;

[0247] T t : temperature of material at t, K;

[0248] T t-1 : temperature of material at t-1, K;

[0249] H in : enthalpy of imported air, kJ;

[0250] H out : enthalpy of exported air, kJ;

[0251] C (p,t) : weighted specific heat capacity of fermentation material at t;

[0252] C (p,t-1) : weighted specific heat capacity of fermentation material at t-1;

[0253] Q loss : heat dissipation of fermentation device, calculated as follows:

[0254] Q loss = 0.5k x A x (T t-1 -T aint ) x At / 1000

[0255] k: heat dissipation coefficient of fermentation device, W / (K.m 2 ), the fermentation device should be insulated to reduce heat dissipation, in this example, k = 0.5 W / (K.m 2 );

[0256] A: contact area of fermentation tank and air, m 2 ;

[0257] T t-1 : temperature of material at t-1, K;

[0258] T aint : temperature of air at t, K;

[0259] coefficient 0.5, the average of material temperature and air temperature is taken as the surface temperature of the fermentation device;

[0260] oxygen consumption is calculated;

[0261] oxygen heat equivalent is dynamically adjusted according to the consumption proportion of degradable organic matter

[0262]

[0263] The mass calculation formula of required oxygen consumption is:

[0264]

[0265] According to Q f,t,true The mass of required oxygen consumption is calculated, and aeration control is executed;

[0266] S4: Aeration control execution;

[0267] Theoretical air volume Q air (m 3 / s) :

[0268]

[0269] ρ air is the density of oxygen;

[0270] Actual control air volume Q v_in(t+1) (m 3 / s)

[0271] Q v_in(t+1) = 110% Q air(t+1)

[0272] The coefficient 110% increases by 10% safety margin.

[0273] Specifically, in an embodiment of the present application, the Kalman filtering method is used to calculate the mass of organic matter m

[0274] The state parameters are selected as the material organic matter mass m y,t-1,true and aerobic fermentation heat Q f,t-1,true at t-1 time, and the material temperature and material mass change are selected as observation parameters;

[0275] The optimal estimation of the time step state parameter at t-1 time is:

[0276] x t-1 = [Q f,t-1,true , m y,t-1,true ] T

[0277] The observation vector is

[0278] z = [T t , Δm t ] T = [T t , m t - m t-1 ] T

[0279] Δm t = m t - mt-1 ;

[0280] The observation matrix is

[0281]

[0282] Based on the linear extrapolation of the change at t-1 time, the prediction value of the material organic matter mass m y,t,pred and the heat Q of aerobic fermentation at t time is calculated. f,t,pred ;

[0283] x t,pred =[Q f,t,pred ,m y,t,pred ] T =[Q f,t-1,true +Q f,t-1 -Q f,t-2 ,m y,t-1,true +m (y,t-1) -m (y,t-2) ] T

[0284] In the initial first Δt time or second Δt time period after the system starts, there is no data at the initial time (t≥2, t-2≥0), which can be simply assumed as 0, and the filter will converge in several time steps.

[0285] Assuming m y,t,pred and Q f,t,pred are known data, and T t and Δm t are unknown values; substitute the intermediate quantity formula, use the calculation unit to find the approximate solution of T t and Δm t , that is, the solution residual of the approximate solution T t and Δm t is <0.001, at this time the approximate solution of T t and Δm t is the prediction value of the parameter, which is recorded as T t,pred and Δm t,pred respectively, that is:

[0286] The compensation residual y t is calculated as:

[0287] y t =[T t -T t,pred ,Δm t -Δm t,pred ] T

[0288] The prior covariance matrix is updated as

[0289] P t|t-1 =Pt +Q

[0290] Update Kalman gain matrix

[0291] K t = P t|t-1 H T (HP t|t-1 H T +R) -1

[0292] Calculate the optimal estimate within the current step

[0293] x t = x t,pred + K t y t

[0294] That is:

[0295] [Q f,t,true ,m y,t,true ] T = [Q f,t,pred ,m y,t,pred ] T + K t y t

[0296] Update covariance:

[0297] P t = (1-K t H)P t|t-1

[0298] Q f,t,true is the heat release in aerobic fermentation in S7;

[0299] According to Q f,t,true , the mass of required oxygen consumption is calculated, and the aeration control is executed.

[0300] Specifically, in an embodiment of the present application, at the beginning of fermentation, the surface area of the fermentation tank is 7.68 m 2 , the initial mass of the material is 1280 kg, the initial moisture content is 66.1%, the initial content of organic matter is 73.7%, and the material monitoring temperature (within 10 days) is shown in the attached Figure 1 , and the comparison of the ventilation volume of the traditional calculation method and the present method is shown in the attached Figure 2 . The calculation method of the traditional ventilation volume is , that is, the ventilation volume of organic matter per minute per cubic meter is 0.1 cubic meter; and the attached Figure 2It can be seen that in the early stage of fermentation, the oxygen consumption is not high at this time when the temperature is low, and it is not necessary and not possible to ventilate a large amount of air to prevent the temperature from being reduced to cause the fermentation to stop. The traditional method of determining ventilation according to the content of organic matter is not applicable here. The time above 55℃ in the aerobic fermentation process carried out by the method is 5 days, and the seed germination index is >80%, which meets the requirements of the Temperature reaching 55℃-65℃ for more than three days and the Germination index being greater than 70% in the Standard for Sludge Treatment and Stabilization in Municipal Wastewater Treatment Plant (CJ / T 510-2017). At the same time, the method calculates the ventilation volume according to the oxygen consumption, and the ventilation volume is greatly reduced; specifically, the ventilation volume of the method within 10 days is 233m 3 , the ventilation volume of the traditional method is 481m 3 , and the ventilation volume is reduced by 51.5%.

[0301] In summary, the present application creatively uses mature and reliable and low-cost temperature and humidity and weighing sensing technology to realize precise aeration control without oxygen probe by constructing a dynamic heat balance model. The bottleneck of easy failure and high cost of traditional oxygen monitoring equipment is effectively avoided, the energy consumption of the fan and the excessive evaporation of water are significantly reduced, the oxygen utilization rate and the system robustness are improved, and a high-reliability and low-cost precise aeration control means is provided for industrialized aerobic fermentation of organic solid waste.

[0302] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, several improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should also be considered as the protection scope of the present application.

Claims

1. An oxygen supply control method for aerobic fermentation of organic biomass, characterized by, The method comprises the following steps: S1: a temperature measuring device and a stirring device are arranged inside the fermentation device to make the temperature distribution in the fermentation device uniform; the fermentation device is provided with a weighing device; S2: before fermentation starts, the total mass of the fermentation material is determined, the fermentation material is divided into three components of water, inorganic matter and organic matter, the water content and the organic matter content of the material are measured, and the initial masses of the three components in the material are calculated; the initial state covariance matrix P0, the measurement noise matrix Q and the process noise matrix R are determined based on the Kalman filtering method; S3: each Δt time is taken as a time step, and the parameters are monitored once in the time step; the monitoring parameters include the temperature, humidity and volume flow and pressure of the inlet and outlet of the fermentation device, the average temperature of the material in the fermentation device and the total mass of the material; the water evaporation amount E in the Δt time is calculated according to the temperature, humidity and flow of the inlet and outlet air; S4: the masses of the three components of water, inorganic matter and organic matter in the fermentation material at time t are respectively: Water quality: m w,t ); Inorganic mass: m n,t ); Organic mass: m (y,t) ; Total mass of the material in the fermentation device: m t ; The mass of the inorganic matter is constant during the fermentation process; Each kilogram of organic matter is decomposed to generate α kg of water during the fermentation process of the material, and α is related to the type of the material; The masses of the three components at time t and time t-1, α and E in each Δt time step satisfy the following relationship: m t = m( w,t )+ m( n,t )+ m (y,t) m t-1 = m( w,t-1 )+ m( n,t-1 )+ m (y,t-1) m( n,t ) = m( n,t-1 ) = m( n,0 ) m( w,t ) = m( w,t-1 ) + a(m (y,t-1) -m (y,t) ) - E S5: the average specific heat capacity of the material in each time step is calculated, and the average specific heat capacity of the material is equal to the average value of the specific heat capacities of the components weighted according to the mass; the heat release amount of aerobic fermentation in each time step is calculated based on a heat balance model; the heat release amount of aerobic fermentation is equal to the sum of the sensible heat change amount of the material, the external heat dissipation amount and the increase amount of the enthalpy of the inlet and outlet air; S6: the target state parameters are determined based on the Kalman filtering method, and the predicted values of the state parameters in each Δt time step are calculated; The prior covariance matrix is updated, the Kalman gain matrix is updated after the residual error is calculated, and finally the optimal estimation is obtained and the state covariance matrix is updated; S7: the oxygen consumption is calculated: the current oxygen equivalent is calculated according to the consumption proportion of the organic matter, the heat release amount of aerobic fermentation is calculated according to the state parameters in the optimal estimation in S6, and the oxygen consumption is obtained by dividing the oxygen equivalent; S8: the theoretical ventilation amount is calculated according to the oxygen consumption, and the actual ventilation amount is calculated by considering a certain margin, and the fan is controlled to operate according to the actual ventilation amount.

2. The oxygen supply control method for aerobic fermentation of organic biomass according to claim 1, characterized by, In S3, the monitoring parameters of the inlet and outlet are measured once in each Δt time step, and the water evaporation amount E in the Δt time is calculated; Temperature of the incoming air T ain ; Outlet air temperature T aout ; Imported air humidity RH in ; Outlet air humidity RH out ; Imported air volume flow Q vin ; Outlet air volume flow Q vout ; Imported air pressure P in ; Air pressure P of the outlet out ; Inlet air saturation vapor pressure P satin : Outlet air saturation vapor pressure P satout : The water evaporation amount E in the Δt time is calculated as follows: E is calculated by substituting the intermediate parameters.

3. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 1, wherein In S4, for sludge, the value range of α is 0.3-0.6, and the value of α of non-sludge material is measured through experiments.

4. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 1, wherein In S5, the average value of each component is calculated as the average specific heat capacity C of the material at time t by mass weighting (p,t) The average specific heat capacity of the material is C (p,w) : specific heat capacity of water; C (p,y) : Specific heat capacity of the organic material, measured. C (p,n) : Specific heat capacity of inorganic substance, measured.

5. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 4, wherein In S5, the heat balance model is constructed as follows: Q f,t = m t x C (p,t) x T t - m t-1 x C (p,t-1) x T t-1 + Q loss + (H out - H in ) Q f,t : heat release of aerobic fermentation of the heat balance model; T t : material temperature at time t; T t-1 : material temperature at time t-1 Q loss : the amount of heat dissipated by the fermentation device H in : enthalpy of inlet air carried H out : enthalpy of the outlet air carried C (p,t) : Weighted specific heat capacity of the fermentation mass at time t C (p,t-1) : Weighted specific heat content of the fermentation mass at time t-1.

6. The oxygen supply control method for aerobic fermentation of organic biomass according to claim 5, characterized by, In S6, the state parameter is selected as the organic matter mass m of the material at time t-1 y,t-1,true and the heat Q released by aerobic fermentation f,t-1,true ; the material temperature and the material mass change are selected as observation parameters; The optimal estimation of the time step state parameters at time t-1 is: x t-1 = [Q f,t-1,true ,m y,t-1,true ] T The observation vector is: z = [T t , Δm t ] T = [T t , m t - m t-1 ] T Δm t = m t - m t-1 ; The observation matrix is: Based on the linear extrapolation of the change at t-1 time, the mass of organic matter of the material at t time m is calculated y,t,pred and the predicted value of the heat Q released by aerobic fermentation f,t,pred ​ x t,pred = [Q f,t,pred ,m y,t,pred ] T = [Q f,t-1,true + Q f,t-1 - Q f,t-2 ,m y,t-1,true + m (y,t-1) - m (y,t-2) ] T In the initial first Δt time or second Δt time period after the system starts, there is no initial time data, and the filter will converge in the continuous iteration time steps by assuming the data to be 0; Assume m y,t,pred and Q f,t,pred are known data, while T t and Δm t are unknown values; substitute the intermediate formula, use the calculation unit to find the approximate solution of T t and Δm t , i.e. the solution residual of the approximate solution T t and Δm t is <0.001, at which time the approximate solution of T t and Δm t is the predicted value of the parameter, respectively recorded as T t,pred and Δm t,pred , i.e. Compensated residual y t Calculation: y t = [T t - T t,pred , Δm t - Δm t,pred ] T The prior covariance matrix is updated P t|t-1 = P t + Q The Kalman gain matrix is updated K t = P t|t-1 H T (HP t|t-1 H T + R) -1 The optimal estimation in the current step is calculated x t = x t,pred + K t y t That is [Q f,t,true ,m y,t,true ] T = [Q f,t,pred ,m y,t,pred ] T + K t y t The covariance is updated P t = (1 - K t H)P t|t-1 Q f,t,true For S7 aerobic fermentation heat release.

7. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 1, wherein In S7, Q loss The amount of heat dissipated by the fermentation device to the outside: Q loss = 0.5 k x A x (T t-1 - T aint ) x Δt / 1000 k: the external convective heat dissipation coefficient of the fermentation device; A: Fermenter air contact area T t-1 : material temperature at time t-1 T aint : air temperature at time t.

8. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 2, wherein In S5, the enthalpy H carried by the outlet air out : H out = m dryout × ((1.006 x T aout + D out ) x (2501 + 1.86 x T aout )) outlet water vapor mass Outlet air moisture content D out : Δt time cumulative output air molar quantity n out : R is the gas constant Outlet water vapor volume fraction Imported air entrained enthalpy H in : H in = m dryin × ((1.006 x T ain + D in ) x (2501 + 1.86 x T ain )) m is the mass of dry air input in Δt dryin : Import air moisture content D in : n: cumulative molar amount of input air in Δt time in : Imported water vapor volume fraction 9. The method of claim 6, wherein the oxygen supply is controlled by measuring the oxygen concentration in the fermentation tank and adjusting the oxygen supply based on the measured oxygen concentration. In S7, oxygen heat equivalent m (y,0) : organic mass at initial time; oxygen consumption The calculation is:

10. The method for controlling oxygen supply of aerobic fermentation of organic biomass according to claim 1, wherein In S8, the actual control air quantity Q v_in is used , aeration is performed, and the margin coefficient ε is taken as 1.1 to 1.3, i.e., Q v_in = εQ air ; Theoretical air flow Q air : p air For air density.

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