Method and device for determining highest safe temperature of hot air during cross-flow drying of fixed bed

Abstract

The invention relates to the technical field of chemical production, in particular to a method and device for determining the highest safe temperature of hot air during cross-flow drying of a fixed bed, and the method comprises the steps: calculating the steady-state temperature of each bed layer in the fixed bed according to the current temperature of the hot air, the self-heating kinetic parameters of materials and the thermophysical properties of the hot air; determining whether the current temperature is a safe temperature or not according to the steady-state temperature of each bed layer and the ignition point of the material, when the current temperature is the safe temperature, judging whether the current temperature meets a preset convergence condition or not, and when the current temperature is not the safe temperature or the current temperature does not meet the preset convergence condition, stopping heating; and iterative calculation is continued until the highest safe temperature of the hot air during fixed bed cross-flow drying is obtained. According to the method, the highest safety temperature in the hot air drying process is accurately judged and determined, so that the spontaneous combustion risk caused by too high temperature is effectively avoided, and meanwhile, the drying efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, and in particular to a method and device for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying. Background Art

[0002] Fixed-bed equipment is often used in industrial production. During its use, regeneration of internal materials is unavoidable. For example, activated carbon adsorption tanks (fixed beds) are widely used in waste gas treatment, wastewater treatment, and decolorization due to their well-developed microporous structure, large specific surface area, and strong adsorption capacity for organic matter. Activated carbon adsorption is a physical adsorption process. When the adsorption capacity reaches saturation, it is inherently wasteful to dispose of it directly as hazardous waste, and there are also significant risks during transportation and storage. Taking these issues into consideration, in actual production, regeneration is often used to restore the performance of activated carbon.

[0003] Currently, there are many methods for regenerating activated carbon. One method involves desorption using high-temperature steam, followed by drying with hot air. When using hot air for drying, it's important to select the appropriate hot air temperature. If the temperature is too low, the drying time will be significantly prolonged, while if the temperature is too high, there may be a risk of self-heating and fire.

[0004] Therefore, clarifying the maximum safe temperature for hot air drying can not only prevent spontaneous heating and fire accidents, but also help the device select the most efficient hot air drying temperature under the premise of safe operation. However, there is currently no method in the industry to determine the maximum safe temperature for hot air drying. Summary of the Invention

[0005] In view of this, the present invention provides a method and device for determining the maximum safe temperature of hot air during fixed bed cross-flow drying.

[0006] In a first aspect, the present invention provides a method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying, comprising the following steps: an acquisition step: acquiring the current temperature of the hot air, the self-thermal dynamic parameters of the material and the thermophysical properties of the hot air; a temperature estimation step: calculating the steady-state temperature of each bed layer in the fixed bed based on the current temperature, the self-thermal dynamic parameters and the thermophysical properties; a safety temperature judgment step: determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material; a safety temperature determination step: when the current temperature is a safe temperature, judging whether the current temperature meets a preset convergence condition, and when the current temperature meets the convergence condition, using the current temperature as the maximum safe temperature of hot air during fixed bed cross-flow drying; when the current temperature is not a safe temperature or the current temperature does not meet the convergence condition, adjusting the current temperature according to the preset current step size to obtain an adjusted temperature, using the adjusted temperature as the new current temperature, and returning to the temperature estimation step and the safety temperature judgment step until the maximum safe temperature of hot air during fixed bed cross-flow drying is obtained.

[0007] This method combines the material's autothermal dynamic parameters with the actual thermophysical properties of the drying process and uses a layer-by-layer fixed-bed steady-state temperature calculation to accurately determine the maximum safe temperature during hot air drying. This effectively avoids the risk of spontaneous combustion caused by excessive temperatures and improves drying efficiency. This method is highly operational and offers precise calculations, providing reliable technical support and theoretical basis for the safety optimization of fixed-bed drying in industrial production.

[0008] In some optional embodiments, determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material includes: for any bed layer, respectively obtaining the first temperature of the current bed layer and the second temperature of the bed layer next to the current bed layer, calculating the difference between the second temperature and the first temperature to obtain a first temperature difference; obtaining a third temperature at the hot air outlet; when all the first temperature differences are greater than 0 and the third temperature is less than the ignition point of the material, determining that the current temperature is a safe temperature; when any first temperature difference is less than 0 or the third temperature is greater than the ignition point of the material, determining that the current temperature is not a safe temperature.

[0009] The present invention simply and effectively determines whether there is a risk of local overheating or spontaneous combustion during the drying process by comparing the temperature difference between adjacent beds and the relationship between the outlet temperature and the ignition point, thereby quickly and accurately determining whether the current temperature is safe, thereby improving the reliability and practicality of the judgment.

[0010] In some optional embodiments, determining whether the current temperature meets the preset convergence condition includes: calculating the difference between the current temperature and the previous iterative temperature to obtain a second temperature difference; determining whether the second temperature difference is less than a preset first threshold; when the second temperature difference is less than the first threshold, determining that the current temperature meets the convergence condition.

[0011] The present invention determines whether convergence has occurred by comparing whether the difference between two adjacent iterative temperatures is less than a set threshold. The method is simple and intuitive and can effectively determine whether the calculation process tends to be stable, thereby improving the efficiency and accuracy of determining the maximum safe temperature.

[0012] In some optional embodiments, when the current temperature is not a safe temperature, adjusting the current temperature according to a preset current step size to obtain an adjusted temperature includes: when the current temperature is not a safe temperature, adjusting the current temperature downward according to the current step size to obtain an adjusted temperature.

[0013] When a safety risk is detected in the current temperature, the present invention adjusts the temperature downward according to a set step size, quickly lowering the operating temperature and avoiding the risk of spontaneous combustion. This ensures a stable and controllable adjustment process, helps efficiently find the upper limit of the safe temperature, and improves the safety and practicality of the entire determination process.

[0014] In some optional embodiments, when the current temperature does not meet the convergence condition, adjusting the current temperature according to the preset current step size to obtain the adjusted temperature includes: when the current temperature does not meet the convergence condition, reducing the current step size to obtain the adjusted step size, and using the adjusted step size as the new current step size; adjusting the current temperature upward according to the new current step size to obtain the adjusted temperature.

[0015] By dynamically reducing the step size and continuing to approach the optimal value when the convergence conditions are not met, the present invention can more finely search for the highest safe temperature, improve the calculation accuracy and stability, make the results more reliable, and at the same time enhance the adaptability and engineering practicality of the method.

[0016] In some optional embodiments, the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying further includes the following steps: obtaining the critical auto-ignition ambient temperature of the material in different containers to obtain a data set; performing fitting based on the data set to obtain a fitting curve; obtaining the slope and intercept of the fitting curve, and determining the self-heating kinetic parameters of the material based on the slope and intercept of the fitting curve.

[0017] The present invention obtains the critical auto-ignition temperature of materials in different containers through experiments and obtains the self-heating kinetic parameters through fitting. The method is simple and the data is reliable, which helps to accurately reflect the actual self-heating characteristics of the material, provides a scientific basis for the determination of safe temperature, and improves the accuracy and practicality of the entire judgment process.

[0018] In a second aspect, a device for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying comprises an acquisition module, a temperature estimation module, a safe temperature judgment module, and a safe temperature determination module; the acquisition module is used to acquire the current temperature of the hot air, the self-thermal dynamic parameters of the material, and the thermophysical properties of the hot air; the temperature estimation module is used to perform a temperature estimation step: calculating the steady-state temperature of each bed layer in the fixed bed based on the current temperature, the self-thermal dynamic parameters, and the thermophysical properties; the safe temperature judgment module is used to perform a safe temperature judgment step: determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material; the safe temperature determination module is used to determine whether the current temperature meets a preset convergence condition when the current temperature is a safe temperature, and use the current temperature as the maximum safe temperature of the hot air during fixed-bed cross-flow drying when the current temperature meets the convergence condition; when the current temperature is not a safe temperature or the current temperature does not meet the convergence condition, adjust the current temperature according to a preset current step size to obtain an adjusted temperature, use the adjusted temperature as the new current temperature, and return to the temperature estimation step and the safe temperature judgment step until the maximum safe temperature of the hot air during fixed-bed cross-flow drying is obtained.

[0019] In a third aspect, the present invention provides a computer device comprising a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to thereby execute the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to the first aspect or any corresponding embodiment thereof.

[0020] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to the first aspect or any corresponding embodiment thereof.

[0021] In a fifth aspect, the present invention provides a computer program product comprising computer instructions for causing a computer to execute the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. 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 any creative work.

[0023] Figure 1This is a flow chart of a method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention;

[0024] Figure 2 is a flow chart of another method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention;

[0025] Figure 3 This is a flow chart of an example of a method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention;

[0026] Figure 4 Schematic diagram of the activated carbon self-thermal kinetics fitting curve according to an embodiment of the present invention;

[0027] Figure 5 Schematic diagram of the dimensions of a fixed bed according to an embodiment of the present invention;

[0028] Figure 6 A schematic diagram of the steady-state temperature results of a fixed bed layer at different hot air temperatures according to an embodiment of the present invention;

[0029] Figure 7 This is a structural block diagram of a device for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying according to an embodiment of the present invention;

[0030] Figure 8 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0032] According to an embodiment of the present invention, an embodiment of a method for determining the maximum safe temperature of hot air during fixed bed through-flow drying is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0033] This embodiment provides a method for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying, which can be used in computer equipment. Figure 1 Flowchart of a method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention. Figure 1As shown, the process includes the following steps:

[0034] Step S101: Acquisition step: Acquisition of the current temperature of the hot air, the self-thermal dynamic parameters of the material and the thermophysical properties of the hot air.

[0035] Specifically, the autothermal kinetic parameters of the material include: activation energy of the material's autothermal reaction, heat release per unit mass of the material's autothermal reaction, and pre-exponential factor of the material's autothermal reaction.

[0036] The thermophysical properties of hot air include: hot air flow rate, hot air density, hot air specific heat capacity, etc.

[0037] Step S102: Temperature estimation step: Calculate the steady-state temperature of each bed layer in the fixed bed according to the current temperature, autothermal dynamic parameters and thermophysical properties.

[0038] Step S103: Safe temperature determination step: determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material.

[0039] In some optional embodiments, determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material includes: for any bed layer, respectively obtaining the first temperature of the current bed layer and the second temperature of the bed layer next to the current bed layer, calculating the difference between the second temperature and the first temperature to obtain a first temperature difference; obtaining a third temperature at the hot air outlet; when all the first temperature differences are greater than 0 and the third temperature is less than the ignition point of the material, determining that the current temperature is a safe temperature; when any first temperature difference is less than 0 or the third temperature is greater than the ignition point of the material, determining that the current temperature is not a safe temperature.

[0040] For example, whether the current temperature is a safe temperature can be determined based on the following criteria:

[0041] If T i+1 -T i ≥0, and the temperature at the hot air outlet T n Lower than the ignition point T of solid materials fire , then determine the current hot air temperature Ta j No temperature fluctuation and fire accident will occur under this temperature. This temperature is the safe temperature Ta. safe , where T i+1 Indicates the second temperature, T i represents the first temperature;

[0042] If any one or more groups of T i+1 -T i <0, or the temperature T at the hot air outlet n Higher than the ignition point T of solid materials fire , then determine the current hot air temperature Ta jA temperature runaway fire accident will occur below this temperature, which is an unsafe temperature Ta. unsafe .

[0043] This embodiment simply and effectively determines whether there is a risk of local overheating or spontaneous combustion during the drying process by comparing the temperature difference between adjacent beds and the relationship between the outlet temperature and the ignition point, thereby quickly and accurately determining whether the current temperature is safe, thereby improving the reliability and practicality of the judgment.

[0044] Step S104: Safety temperature determination step: When the current temperature is a safety temperature, determine whether the current temperature meets the preset convergence condition. When the current temperature meets the convergence condition, use the current temperature as the maximum safe temperature of hot air during fixed bed cross-flow drying; when the current temperature is not a safety temperature or the current temperature does not meet the convergence condition, adjust the current temperature according to the preset current step size to obtain an adjusted temperature, use the adjusted temperature as the new current temperature, and return to the temperature estimation step and the safety temperature judgment step until the maximum safe temperature of hot air during fixed bed cross-flow drying is obtained.

[0045] In some optional embodiments, determining whether the current temperature satisfies a preset convergence condition includes: calculating the difference between the current temperature and the temperature of the previous iteration to obtain a second temperature difference; determining whether the second temperature difference is less than a preset first threshold; and determining that the current temperature satisfies the convergence condition when the second temperature difference is less than the first threshold. For example, Ta unsafe -Ta safe ≤2 is used as the convergence condition. Convergence is determined by comparing whether the difference between two adjacent iterative temperatures is less than a set threshold. This method is simple and intuitive, and can effectively determine whether the calculation process is stable, thereby improving the efficiency and accuracy of determining the maximum safe temperature.

[0046] In some optional embodiments, when the current temperature is not a safe temperature, adjusting the current temperature according to a preset current step size to obtain an adjusted temperature includes: when the current temperature is not a safe temperature, adjusting the current temperature downward according to the current step size to obtain the adjusted temperature. Thus, when a safety risk is detected with the current temperature, downwardly adjusting the temperature according to the preset step size can quickly lower the operating temperature and mitigate the risk of spontaneous combustion, while ensuring a stable and controllable adjustment process, facilitating efficient identification of a safe temperature upper limit, and improving the safety and practicality of the entire determination process.

[0047] In some optional embodiments, when the current temperature does not meet the convergence condition, adjusting the current temperature according to a preset current step size to obtain an adjusted temperature includes: when the current temperature does not meet the convergence condition, reducing the current step size to obtain an adjusted step size, and using the adjusted step size as a new current step size; and adjusting the current temperature upward according to the new current step size to obtain an adjusted temperature. Thus, by dynamically reducing the step size when the convergence condition is not met and continuing to approach the optimal value, a more refined search for the highest safe temperature is possible, improving calculation accuracy and stability, making the results more reliable, and enhancing the adaptability and engineering practicality of the method.

[0048] In summary, this example combines the material's autothermal kinetic parameters with the actual thermophysical properties of the drying process, and employs a layer-by-layer calculation of the fixed-bed steady-state temperature to accurately determine the maximum safe temperature during hot air drying. This effectively avoids the risk of spontaneous combustion caused by excessive temperatures while simultaneously improving drying efficiency. This method, with its robust operability and precise calculations, provides reliable technical support and theoretical basis for the safety optimization of fixed-bed drying in industrial production.

[0049] This embodiment provides a method for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying, which can be used in computer equipment. Figure 2 FIG. 1 is a flow chart of another method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0050] Step S201: Acquire the critical auto-ignition ambient temperature of the material in different containers to obtain a data set.

[0051] Specifically, the critical self-ignition ambient temperature of the material in different containers can be obtained using a solid material self-heating test instrument, wherein the solid material self-heating test instrument includes but is not limited to an oven-basket test instrument and a Dewar flask test instrument.

[0052] The shape of the container is a solid of revolution, including but not limited to a cube, a cylinder, and a sphere.

[0053] Specifically, the critical auto-ignition ambient temperature Tc of 3 to 6 groups of containers with the same shape but different sizes can be obtained.

[0054] When the container is a cylinder or a sphere, the radius of the container in the plurality of containers having the same shape but different sizes is between 2 and 20 cm.

[0055] Step S202: performing fitting according to the data set to obtain a fitting curve.

[0056] Specifically, you can and Fitting is performed to obtain the fitting curve, where δc is the critical dimensionless heat generation rate, Tc is the critical auto-ignition ambient temperature, and r is the radius of the container.

[0057] Step S203: Obtain the slope and intercept of the fitting curve, and determine the autothermal kinetic parameters of the material based on the slope and intercept of the fitting curve.

[0058] As mentioned above, the autothermal kinetic parameters of the material include: the activation energy of the material's autothermal reaction, the heat released per unit mass of the material's autothermal reaction, and the pre-exponential factor of the material's autothermal reaction.

[0059] Specifically, the activation energy of the material autothermal reaction can be obtained using the slope of the fitting curve, and the heat released per unit mass of the material and the pre-exponential factor of the material autothermal reaction can be obtained based on the intercept of the fitting curve.

[0060] For example, you can use Calculate the activation energy of the material's autothermal reaction, where B represents the slope of the fitting curve, E represents the activation energy of the material's autothermal reaction, and R represents the molar gas constant.

[0061] For example, you can use Calculate the heat released per unit mass of the material during the reaction process and the pre-exponential factor of the material's autothermal reaction. Where C represents the intercept of the fitting curve, E represents the activation energy of the material's autothermal reaction, J / mol; Q represents the heat released per unit mass of the material's autothermal reaction, J / kg; A0 represents the pre-exponential factor of the material's autothermal reaction, s -1 ; ρ represents the bulk density of the material in kg / m3, λ represents the thermal conductivity of the material, W / (m·K).

[0062] Step S204: obtaining the current temperature and thermophysical properties of the hot air.

[0063] Step S205: Calculate the steady-state temperature of each bed layer in the fixed bed according to the current temperature, autothermal dynamic parameters and thermophysical properties.

[0064] In some optional embodiments, the bed layer of the fixed bed can be divided into n calculation elements. Given an initial hot air temperature Ta, the current temperature (i.e., the initial hot air temperature Ta), the autothermal dynamic parameters and the thermophysical properties are input into a preset first formula to calculate the steady-state temperature of each bed layer in the fixed bed.

[0065] The first formula is:

[0066]

[0067] Among them, m c Indicates the mass of each microelement of activated carbon, kg; T i represents the temperature of the ith element, K; Ti+1 Indicates the temperature of the i+1th element, K; F air Indicates the flow rate of hot air, m 3 / s;ρ air Indicates the density of hot air, kg / m 3 ; Cp air = represents the specific heat capacity of hot air, J / kg / K; E represents the activation energy of the material's autothermal reaction, J / mol; Q represents the heat released per unit mass of the material's autothermal reaction, J / kg; A0 represents the pre-exponential factor of the material's autothermal reaction, s -1 .

[0068] For example, the thickness of each divided microelement is between 0.1-100 mm.

[0069] Step S206: Determine whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material; when the current temperature is not a safe temperature, proceed to step S207; when the current temperature is a safe temperature, proceed to step S208.

[0070] Step S207: Adjust the current temperature downward according to the current step size to obtain an adjusted temperature, set the adjusted temperature as the new current temperature, and return to step S205.

[0071] Step S208: Determine whether the current temperature meets the preset convergence condition. When the current temperature does not meet the preset convergence condition, proceed to step S209; when the current temperature meets the preset convergence condition, obtain the maximum safe temperature of hot air during fixed bed cross-flow drying.

[0072] Step S209: Reduce the current step length to obtain an adjusted step length, and use the adjusted step length as the new current step length.

[0073] Step S210: Adjust the current temperature upward according to the new current step size to obtain an adjusted temperature, set the adjusted temperature as the new current temperature, and return to step S205.

[0074] In order to explain more clearly the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to an embodiment of the present invention, a specific example is given. Figure 3 As described, this example includes the following steps:

[0075] Taking an activated carbon adsorption tank (with insulation layer) of 4.8m high and 1.6m inner diameter as an example, the safe temperature calculation method for hot air flow drying after steam desorption is described in detail. The activated carbon bed height is 2.72m and the inner diameter is 1.2m. The materials adsorbed by the activated carbon are acrylic monomers such as styrene, MMA, AA, BA, and EHA. The bulk density of the adsorbed saturated activated carbon is 790kg / m 3, specific heat capacity 1.07kJ / kg / K, solid thermal conductivity 0.1264W / m / K, hot air is introduced from the top of the activated carbon tank and exhausted from the bottom. There is a gas distributor on the top of the activated carbon bed. The hot air passes through the activated carbon bed evenly in a plug flow, and the hot air flow rate is 1500m 3 / h, air specific heat capacity 1.008kJ / kg / K, air density 1.293kg / m 3 .

[0076] In step 1, the critical auto-ignition ambient temperatures Tc1, Tc2, Tc3, and Tc4 of the material in the basket (cube with side lengths of 2.5 cm, 5 cm, 7.5 cm, and 10 cm, respectively) were obtained using an oven-basket test instrument. The results were as follows:

[0077]

[0078] Step 2, fitting and The curve is obtained with a slope of B = -10.118 and an intercept of C = 43.639, and the autothermal kinetic parameters of the material are calculated: activation energy E is 84.121 kJ / mol and Q*A0 = 1.44*10^11 W / kg. The autothermal kinetic fitting curve of the activated carbon material is shown in Figure 4 .

[0079] Step 3, the dimensions of the activated carbon tank and activated carbon bed are shown in Figure 5 The activated carbon bed (2.72m high) is divided into 2720 microelements in the vertical direction, where each microelement is 1mm thick. Assuming an initial hot air temperature Ta = Min (Tc) = 136.2°C, the steady-state temperature Ti of each microelement of the fixed bed is iteratively calculated based on the autothermal dynamic parameters of the material and the flow rate, density and specific heat capacity of the hot air.

[0080] Step 4: Calculate the temperature Ti of each microelement of the fixed bed at steady state according to the above formula, and obtain the safe temperature of hot air during fixed bed cross-flow drying according to the following judgment conditions:

[0081] When Ta = 136.2℃, the iteratively calculated steady-state temperature of each microelement of the fixed bed appears T i+1 -T i <0, it is determined that when the hot air temperature Ta = 136.2 ° C, a temperature runaway fire accident will occur on the fixed bed, and the temperature is assigned to the unsafe temperature Ta unsafe =136.2℃;

[0082] The hot air temperature is changed to Ta = 136.2-8 = 128.2 °C in steps of 8 °C. The iteratively calculated steady-state temperature of each microelement of the fixed bed satisfies T i+1 -T i ≥0, and the temperature at the hot air outlet T n =153.8℃ lower than the ignition point T of solid materials fire =300℃, it is determined that when the hot air temperature Ta = 128.2℃, the fixed bed will not have a temperature runaway fire accident, and the temperature is assigned to the safety temperature Ta safe =128.2℃;

[0083] Ta unsafe -Ta safe =8℃>2℃, it is necessary to change the hot air temperature to further calculate the drying safety temperature;

[0084] With (Ta unsafe -Ta safe ) / 2=4℃ is the step size to change the hot air temperature to Ta=128.2+4=132.2℃, and the iteratively calculated steady-state temperature of each microelement of the fixed bed satisfies T i+1 -T i ≥0, and the temperature at the hot air outlet T n =189.8℃ lower than the ignition point T of solid materials fire =300℃, it is determined that when the hot air temperature Ta = 132.2℃, the fixed bed will not have a temperature runaway fire accident, and the temperature is assigned to the safety temperature Ta safe =132.2℃;

[0085] Ta unsafe -Ta safe =4℃>2℃, it is necessary to change the hot air temperature to further calculate the drying safety temperature;

[0086] With (Ta unsafe -Ta safe ) / 2=2℃ is the step size to change the hot air temperature to Ta=132.2+2=134.2℃, and the iteratively calculated steady-state temperature of each microelement of the fixed bed appears T i+1 -T i <0, it is determined that when the hot air temperature Ta = 134.2 ° C, a temperature runaway fire accident will occur on the fixed bed, and the temperature is assigned to the unsafe temperature Ta unsafe =134.2℃;

[0087] Ta unsafe -Ta safe ≤2, the safe temperature Ta at this time safe =132.2℃ is the maximum hot air drying temperature allowed for the fixed bed under this working condition.

[0088] Figure 6 Schematic diagram of the steady-state temperature results of the fixed bed layer at different hot air temperatures according to an embodiment of the present invention, as shown in FIG. Figure 6 It can be seen that when the current temperature is 136.2℃ and 134.2℃, there is no convergence, so it is an unsafe temperature. When the current temperature is 128.2℃ and 132.2℃, there is convergence and the steady-state temperature is lower than the ignition point of the material, both of which are safe temperatures. The unsafe temperature 134.2℃ - the safe temperature 132.2℃ ≤ 2℃, so 132.2℃ is used as the maximum hot air drying temperature.

[0089] The method for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying provided in this embodiment accurately obtains the maximum hot air drying temperature that can ensure safe operation through a simple solid self-heating test instrument and a self-heating model that is more in line with actual working conditions, providing a basis for selecting economical and safe operating conditions for the device.

[0090] This embodiment also provides a device for determining the safe maximum temperature of hot air during fixed-bed through-flow drying. This device is used to implement the above-mentioned embodiments and preferred embodiments, and details already described will not be repeated. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented using software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0091] This embodiment provides a device for determining the maximum safe temperature of hot air during fixed bed cross-flow drying. Figure 7 Shown, including:

[0092] Acquisition module 701, used to obtain the current temperature of the hot air, the self-thermal dynamic parameters of the material and the thermophysical properties of the hot air;

[0093] The temperature estimation module 702 is used to perform the temperature estimation step: calculating the steady-state temperature of each bed layer in the fixed bed according to the current temperature, the self-thermal dynamic parameters and the thermophysical properties;

[0094] The safety temperature judgment module 703 is used to perform the safety temperature judgment step: determine whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material;

[0095] The safety temperature determination module 704 is used to determine whether the current temperature meets the preset convergence condition when the current temperature is a safe temperature. When the current temperature meets the convergence condition, the current temperature is used as the maximum safe temperature of the hot air during fixed bed cross-flow drying; when the current temperature is not a safe temperature or the current temperature does not meet the convergence condition, the current temperature is adjusted according to the preset current step size to obtain an adjusted temperature, the adjusted temperature is used as the new current temperature, and the temperature estimation step and the safety temperature judgment step are returned until the maximum safe temperature of the hot air during fixed bed cross-flow drying is obtained.

[0096] In some optional implementations, the safety temperature determination module 704 is specifically used to: for any bed layer, respectively obtain the first temperature of the current bed layer and the second temperature of the bed layer next to the current bed layer, calculate the difference between the second temperature and the first temperature, and obtain the first temperature difference; obtain the third temperature at the hot air outlet; when all the first temperature differences are greater than 0 and the third temperature is less than the ignition point of the material, determine that the current temperature is a safe temperature; when any first temperature difference is less than 0 or the third temperature is greater than the ignition point of the material, determine that the current temperature is not a safe temperature.

[0097] In some optional embodiments, the safety temperature determination module 704 is specifically used to: calculate the difference between the current temperature and the previous iterative temperature to obtain a second temperature difference; determine whether the second temperature difference is less than a preset first threshold; when the second temperature difference is less than the first threshold, determine that the current temperature meets the convergence condition.

[0098] In some optional implementations, the safe temperature determination module 704 is specifically configured to: when the current temperature is not a safe temperature, adjust the current temperature downward according to the current step size to obtain an adjusted temperature.

[0099] In some optional embodiments, the safety temperature determination module 704 is specifically used to: when the current temperature does not meet the convergence condition, reduce the current step size to obtain an adjusted step size, and use the adjusted step size as the new current step size; adjust the current temperature upward according to the new current step size to obtain an adjusted temperature.

[0100] In some optional embodiments, the apparatus for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying further includes a module for determining autothermal kinetic parameters. The module is configured to: obtain critical autoignition ambient temperatures of the material in different containers to obtain a data set; perform fitting based on the data set to obtain a fitting curve; obtain the slope and intercept of the fitting curve; and determine the autothermal kinetic parameters of the material based on the slope and intercept of the fitting curve.

[0101] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0102] The device for determining the maximum safe temperature of hot air during fixed bed through-flow drying in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0103] The embodiment of the present invention also provides a computer device having the above Figure 7 The device shown is for determining the maximum safe temperature of hot air during fixed bed through-flow drying.

[0104] See also Figure 8 , Figure 8 is a structural diagram of a computer device provided by an optional embodiment of the present invention, such as Figure 8 As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 8 A processor 10 is taken as an example.

[0105] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0106] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0107] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0108] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0109] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Figure 8 The bus connection is taken as an example.

[0110] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0111] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0112] A portion of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the form in which the computer program instruction exists in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc. Accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium that can be accessed by the computer.

[0113] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying, characterized in that: include: Acquisition step: acquiring the current temperature of the hot air, the self-thermal dynamic parameters of the material and the thermophysical properties of the hot air; Temperature estimation step: calculating the steady-state temperature of each bed layer in the fixed bed according to the current temperature, the autothermal dynamic parameters and the thermophysical properties; Safety temperature judgment step: determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material; Safety temperature determination step: when the current temperature is a safety temperature, determine whether the current temperature meets the preset convergence condition. When the current temperature meets the convergence condition, use the current temperature as the maximum safe temperature of the hot air during the fixed bed cross-flow drying. When the current temperature is not a safety temperature or the current temperature does not meet the convergence condition, adjust the current temperature according to the preset current step size to obtain an adjusted temperature, use the adjusted temperature as the new current temperature, and return to the temperature estimation step and the safety temperature judgment step until the maximum safe temperature of the hot air during the fixed bed cross-flow drying is obtained.

2. The method according to claim 1, characterized in that Determining whether the current temperature is a safe temperature based on the steady-state temperature of each bed layer and the ignition point of the material includes: For any bed layer, respectively obtaining a first temperature of the current bed layer and a second temperature of the bed layer next to the current bed layer, and calculating a difference between the second temperature and the first temperature to obtain a first temperature difference; obtaining a third temperature at a hot air outlet; When all the first temperature differences are greater than 0 and the third temperature is less than the ignition point of the material, the current temperature is determined to be a safe temperature; When any of the first temperature differences is less than 0 or the third temperature is greater than the ignition point of the material, it is determined that the current temperature is not a safe temperature.

3. The method according to claim 1, characterized in that The determining whether the current temperature satisfies a preset convergence condition includes: Calculating the difference between the current temperature and the previous iterative temperature to obtain a second temperature difference; Determining whether the second temperature difference is less than a preset first threshold; When the second temperature difference is less than the first threshold, it is determined that the current temperature meets the convergence condition.

4. The method according to claim 1, wherein When the current temperature is not a safe temperature, adjusting the current temperature according to a preset current step length to obtain an adjusted temperature includes: When the current temperature is not a safe temperature, the current temperature is adjusted downward according to the current step size to obtain the adjusted temperature.

5. The method according to claim 1, wherein When the current temperature does not meet the convergence condition, adjusting the current temperature according to a preset current step size to obtain an adjusted temperature includes: When the current temperature does not meet the convergence condition, the current step size is reduced to obtain an adjusted step size, and the adjusted step size is used as a new current step size; The current temperature is adjusted upward according to the new current step size to obtain the adjusted temperature.

6. The method according to claim 1, characterized in that Also includes: Obtaining the critical auto-ignition ambient temperature of the material in different containers to obtain a data set; Perform fitting according to the data set to obtain a fitting curve; The slope and intercept of the fitting curve are obtained, and the autothermal kinetic parameters of the material are determined according to the slope and intercept of the fitting curve.

7. A device for determining the maximum safe temperature of hot air during fixed bed cross-flow drying, characterized in that: include: An acquisition module, used to obtain the current temperature of the hot air, the self-thermal dynamic parameters of the material and the thermophysical properties of the hot air; a temperature estimation module, configured to perform a temperature estimation step: calculating a steady-state temperature of each bed layer in the fixed bed according to the current temperature, the autothermal dynamic parameter, and the thermophysical property; A safety temperature judgment module is used to perform a safety temperature judgment step: determining whether the current temperature is a safe temperature according to the steady-state temperature of each bed layer and the ignition point of the material; A safety temperature determination module is used to determine whether the current temperature meets a preset convergence condition when the current temperature is a safety temperature, and to use the current temperature as the maximum safe temperature of the hot air during the fixed bed cross-flow drying when the current temperature meets the convergence condition; when the current temperature is not a safety temperature or the current temperature does not meet the convergence condition, adjust the current temperature according to a preset current step size to obtain an adjusted temperature, use the adjusted temperature as the new current temperature, and return to the temperature estimation step and the safety temperature judgment step until the maximum safe temperature of the hot air during the fixed bed cross-flow drying is obtained.

8. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to any one of claims 1 to 6 by executing the computer instructions.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, which are used to enable a computer to execute the method for determining the maximum safe temperature of hot air during fixed-bed cross-flow drying according to any one of claims 1 to 6.

10. A computer program product, characterized in that The method comprises computer instructions for causing a computer to execute the method for determining the maximum safe temperature of hot air during fixed bed cross-flow drying according to any one of claims 1 to 6.

Images