Method for controlling the outlet temperature of a conditioning machine

Abstract

The application provides a moisture regaining machine outlet temperature control method for controlling the outlet temperature of a moisture regaining machine, comprising the following steps: calculating the specific heat value of each raw material in a tobacco formula respectively; calculating the target steam flow required to be input into the moisture regaining machine when the moisture regaining machine processes each raw material according to the specific heat value of each raw material and a preset outlet temperature; inputting the raw material corresponding to each specific heat value into the moisture regaining machine in the order of increasing or decreasing specific heat value; and adjusting the steam flow to the target steam flow corresponding to each raw material in turn according to the order of inputting each raw material into the moisture regaining machine. The application can reduce the fluctuation of the outlet temperature of the moisture regaining machine and improve the stability of the outlet temperature.

Description

Technical Field

[0001] This invention relates to the field of tobacco processing technology, and in particular to a method for controlling the outlet temperature of a rehumidifier. Background Technology

[0002] In cigarette manufacturing lines, the loosening and rehydration process is a crucial step in the tobacco processing technology. The outlet temperature of the rehydration machine is one of the main indicators for measuring the processing intensity of the loosening and rehydration process, and it also has a direct or indirect impact on the control of subsequent processes and the stability of product quality. The rehydration machine is used to transport raw tobacco shreds and apply high-temperature steam to them, causing the raw tobacco shreds to absorb moisture and expand, becoming loose and resilient, preventing the tobacco shreds from breaking. However, when steam is stably input into the rehydration machine, the outlet temperature of the rehydration machine fluctuates significantly. Summary of the Invention

[0003] The purpose of this invention is to solve the technical problem of temperature fluctuation at the outlet of a rehumidifier. This invention provides a method for controlling the outlet temperature of a rehumidifier, which can improve the stability of the outlet temperature.

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a method for controlling the outlet temperature of a rehumidifier, used to control the outlet temperature of the rehumidifier. Each raw material in the tobacco formula passes through the rehumidifier sequentially and is then output from the outlet of the rehumidifier. The outlet temperature control method includes:

[0005] Calculate the specific heat value of each raw material separately;

[0006] Based on the specific heat value of each raw material, the preset outlet temperature, and the first function relationship, calculate the target steam flow rate of the rehumidifier when processing each raw material.

[0007] According to the order in which each raw material enters the rehumidifier, the steam flow rate is adjusted to the target steam flow rate corresponding to each raw material.

[0008] Optionally, the order in which the raw materials enter the rehumidifier is as follows: the raw materials corresponding to each specific calorific value are input into the rehumidifier in order of increasing or decreasing specific calorific value.

[0009] Optionally, the specific calorific value of each raw material in the tobacco formulation is calculated separately, including:

[0010] Control the steam flow rate to ensure a stable input;

[0011] Each raw material is fed separately into the rehumidifier;

[0012] The outlet temperature of each raw material output from the rehumidifier was recorded separately.

[0013] The specific heat value of each raw material is calculated based on the outlet temperature, steam flow rate, and the second function relationship.

[0014] Optionally, the specific calorific value of each raw material in the tobacco formulation is calculated separately, including:

[0015] Control the steam flow rate to ensure a stable input, and feed each raw material into the rehumidifier in sequence;

[0016] Statistical analysis of the outlet temperature was performed, and a curve showing the change of outlet temperature over time was plotted.

[0017] Calculate the specific heat value of each raw material based on the curve and steam flow rate.

[0018] Optionally, the content of each raw material in the formula is equal, and the specific heat value of each raw material is calculated based on the curve and steam flow rate, including:

[0019] The curve is divided into multiple intervals in chronological order, with the number of intervals equal to the number of raw materials.

[0020] Calculate the average outlet temperature within each interval, and regard the average value as the outlet temperature corresponding to each raw material;

[0021] The specific heat value of each raw material is calculated based on the outlet temperature, steam flow rate, and the second function relationship.

[0022] Optionally, the first functional relationship is:

[0023]

[0024] Where C is the specific heat value, q is the target steam flow rate, η is the steam heat utilization rate, M is the feed flow rate, t is the preset outlet temperature, t0 is the initial temperature of the feed, and a is the energy density of the steam.

[0025] Optionally, the second functional relationship is:

[0026]

[0027] Where C is the specific heat value, Q is the steam flow rate, η is the steam heat utilization rate, M is the feed flow rate, T is the outlet temperature, T0 is the initial temperature of the feed, and a is the energy density of the steam.

[0028] Optionally, the flow rate and weight of each raw material output by the rehumidifier are constant values, and the rehumidifier can adjust the steam flow rate to the target steam flow rate corresponding to the raw material at fixed intervals.

[0029] Optionally, the fixed duration is the ratio of the weight to the flow rate of each raw material.

[0030] Optionally, the rehumidifier is equipped with a steam outlet for supplying high-temperature steam into the rehumidifier. When each raw material reaches the steam outlet, the steam flow rate is adjusted to the target steam flow rate corresponding to that raw material.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The embodiments of the present invention calculate the target steam flow rate corresponding to each raw material input into the rehumidifier based on the specific heat value and the preset outlet temperature; input each raw material into the rehumidifier in sequence; and adjust the steam flow rate in sequence to the target flow rate value matching each raw material, which can ensure that the outlet temperature of the rehumidifier is not affected by the specific heat value of each raw material and improve the stability of the outlet temperature. Attached Figure Description

[0033] Figure 1 A flowchart of a method for controlling the outlet temperature of a rehumidifier according to an embodiment of the present invention is shown. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0035] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0037] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0038] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0040] In existing technologies, when steam is stably input into a rehumidifier that transports tobacco raw materials, the outlet temperature of the rehumidifier fluctuates significantly. Further investigation by the applicant revealed that tobacco is composed of different types of tobacco shreds, each with a different specific heat value. Therefore, when the same flow rate of steam is applied to each type of raw material, their temperatures exhibit different characteristics. Consequently, when steam is stably input into the rehumidifier, the outlet temperature fluctuates depending on the type of raw material being processed.

[0041] To address the aforementioned technical problems, embodiments of the present invention provide a method for controlling the outlet temperature of a rehumidifier, which controls the outlet temperature of the rehumidifier, wherein each raw material in the tobacco formula is output from the outlet of the rehumidifier after passing through it in sequence. Figure 1 The outlet temperature control method shown in this embodiment includes:

[0042] Step A1: Calculate the specific heat value of each raw material.

[0043] Step A2: Based on the specific heat value of each raw material, the preset outlet temperature, and the first function relationship, calculate the target steam flow rate of the rehumidifier when processing each raw material.

[0044] Step A3: According to the order in which each raw material enters the rehumidifier, adjust the steam flow rate to the target steam flow rate corresponding to each raw material.

[0045] Specifically, due to the different types of raw materials, their specific heat values ​​also differ. For raw materials with the same temperature rise, those with higher specific heat values ​​absorb more heat than those with lower specific heat values. Therefore, a larger steam flow rate is required for raw materials with higher specific heat values ​​to ensure their temperature rise is equal to that of raw materials with lower specific heat values. This application calculates the target steam flow rate for each raw material entering the rehumidifier based on its specific heat value, preset outlet temperature, and a first functional relationship. This allows for adjusting the steam flow rate in the rehumidifier according to the type of raw material, ensuring that the temperature exhibited by each raw material after absorbing heat from the steam is close to the preset outlet temperature. By controlling the target steam flow rate to match the specific heat value of the raw material, the outlet temperature of the rehumidifier can be guaranteed to be unaffected by the specific heat value of each raw material, thereby improving the stability of the outlet temperature.

[0046] Furthermore, the first functional relationship is:

[0047]

[0048] Where C is the specific heat value (unit: kJ / (kg℃)); q is the target steam flow rate (unit: kg / h), and in this embodiment, the target steam flow rate for each raw material is 150–600 kg / h; η is the steam heat utilization rate (percentage); M is the raw material flow rate (unit: kg / h); t is the preset outlet temperature (unit: ℃), which is also the preset temperature of the raw material after rehumidification and heating; t0 is the initial temperature of the raw material (unit: ℃), which is generally the room temperature at the raw material storage location; therefore, (t-t0) is the temperature increase of the raw material; a is the energy density of the steam (i.e., specific enthalpy, unit: kJ / kg). Specifically, during the process of steam contacting the raw material, part of the heat of the steam is absorbed by the raw material and the other part is lost to the environment. The ratio of the heat absorbed by the raw material to the total heat of the steam is the steam heat utilization rate η, which ranges from 20% to 60%. The steam utilization rate is related to the ambient temperature. In winter, the ambient temperature is low, and the steam heat is lost to the outside through the shell and outlet of the rehumidifier; therefore, the steam heat utilization rate in winter is 20%. In summer, the ambient temperature is high, and less heat is lost from the steam to the outside, so the steam utilization rate is 60%. When the ambient temperature is between winter and summer temperatures, the steam heat utilization rate is between 20% and 60%. According to the process requirements, the outlet temperature t is 55±3℃. To ensure the accuracy of temperature control, the outlet temperature t is taken as 55℃ here.

[0049] Furthermore, the order in which the raw materials enter the rehumidifier is as follows: raw materials corresponding to each specific calorific value are input into the rehumidifier in order of increasing or decreasing specific calorific value. Since the target steam flow rate corresponding to each raw material is proportional to its specific calorific value, in order to maintain a stable preset outlet temperature, it is only necessary to gradually adjust the opening of the steam valve in an increasing or decreasing order (in the same direction as the change in specific calorific value). There is no need to adjust the valve in reverse during the steam input process. This not only facilitates adjustment but also prevents fatigue damage to the steam delivery pipeline caused by sudden changes in the steam valve opening.

[0050] This application does not limit the method for calculating the specific heat value of each raw material. To facilitate understanding by those skilled in the art, the following two embodiments illustrate the method for calculating the specific heat value of each raw material.

[0051] Example 1

[0052] The specific calorific value of each raw material in the tobacco formulation was calculated separately, including:

[0053] Control the steam flow rate to ensure a stable input;

[0054] Each raw material is fed separately into the rehumidifier;

[0055] The outlet temperature of each raw material output from the rehumidifier was recorded separately.

[0056] The specific heat value of each raw material is calculated based on the outlet temperature, steam flow rate, and the second function relationship.

[0057] Example 2

[0058] The specific calorific value of each raw material in the tobacco formulation was calculated separately, including:

[0059] Control the steam flow rate to ensure a stable input, and feed each raw material into the rehumidifier in sequence;

[0060] Statistical analysis of the outlet temperature was performed, and a curve showing the change of outlet temperature over time was plotted.

[0061] Calculate the specific heat value of each raw material based on the curve and steam flow rate.

[0062] Furthermore, since the content of each raw material in the formula is equal, the specific heat value of each raw material is calculated based on the curve and steam flow rate, including:

[0063] The curve is divided into multiple intervals in chronological order, with the number of intervals equal to the amount of raw materials, and each interval having an equal duration.

[0064] The average outlet temperature within each interval is calculated, and this average value is considered as the outlet temperature corresponding to each raw material. Specifically, the methods for calculating the average outlet temperature within each interval include the calculus method and the approximate calculation method. The calculus method involves simulating an approximate function of the curve within each interval, integrating the function with the outlet temperature within that interval, and then dividing by the time length of that interval to obtain the average outlet temperature. The approximate calculation method involves taking the average outlet temperature at both ends of the interval.

[0065] The specific heat value of each raw material is calculated based on the outlet temperature, steam flow rate, and the second function relationship.

[0066] The above embodiments are further detailed descriptions of the thermal insulation components, and it should not be assumed that the methods for calculating the specific heat value of each raw material are limited to these descriptions. All equivalent implementations or modifications that do not depart from the scope of this application should be included within the scope of this application.

[0067] Specifically, the second functional relationship in Embodiment 1 and Embodiment 2 above is as follows:

[0068]

[0069] Where C is the specific heat value (unit: kJ / (kg℃)); Q is the target steam flow rate (unit: kg / h); η is the steam heat utilization rate (percentage); M is the raw material flow rate (unit: kg / h); T is the preset outlet temperature (unit: ℃), which is also the preset temperature of the raw material after rehydration and heating; T0 is the initial temperature of the raw material (unit: ℃), which is generally the room temperature of the raw material storage location; therefore, (T-T0) is the temperature increase of the raw material; a is the energy density of the steam (i.e., specific enthalpy, unit: kJ / kg).

[0070] Specifically, the specific heat value C of each raw material is the ratio of the heat absorbed per unit weight of raw material to its temperature increase (T-T0). ηQa is the heat absorbed by the raw material per unit time, and M is the flow rate of the raw material, i.e., the weight of raw material transported by the rehumidifier per unit time. The ratio of the heat absorbed by the raw material to the total heat of the steam is the steam heat utilization rate η. In winter, when the ambient temperature is low, the steam heat utilization rate is approximately 20%; in summer, when the ambient temperature is high, the steam utilization rate is approximately 60%. Specifically, in winter, the ambient temperature is approximately 6℃, and the steam heat is also lost to the outside through the shell and outlet of the rehumidifier, so the steam heat utilization rate is low in winter. In summer, the ambient temperature is high, approximately 34℃, and less heat is lost to the outside, so the steam utilization rate is high in summer. In other seasons, when the ambient temperature is between 6℃ and 34℃, the steam heat utilization rate is between 20% and 60%. According to the process requirements, the outlet temperature t is 55±3℃. To ensure the accuracy of temperature control, the outlet temperature t is taken as 55℃ here.

[0071] Furthermore, the flow rate and weight of each raw material input into the rehumidifier are constant (i.e., the weight and flow rate of each raw material are equal). The rehumidifier can adjust the steam flow rate to the target steam flow rate corresponding to that raw material at fixed intervals. Specifically, this fixed interval is the ratio of the weight of each raw material to the flow rate of the raw material conveyed by the rehumidifier, which is the duration for which the rehumidifier applies steam to each raw material. Specifically, the rehumidifier is equipped with a steam outlet for supplying high-temperature steam. When each raw material reaches the steam outlet, the steam flow rate is adjusted to the target steam flow rate corresponding to that raw material.

[0072] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A method for controlling the outlet temperature of a rehumidifier, used to control the outlet temperature of the rehumidifier, wherein each raw material in a tobacco formula passes through the rehumidifier sequentially and is output from the outlet of the rehumidifier, characterized in that, The outlet temperature control method includes: Calculate the specific heat value of each raw material separately; Based on the specific heat value, preset outlet temperature and first functional relationship of each raw material, the target steam flow rate of the rehumidifier needs to be input when processing each raw material. According to the order in which each raw material enters the rehumidifier, the steam flow rate is adjusted sequentially to the target steam flow rate corresponding to each raw material.

2. The temperature control method as described in claim 1, characterized in that, The order in which the raw materials enter the rehumidifier is as follows: the raw materials corresponding to each specific heat value are input into the rehumidifier in order of increasing or decreasing specific heat value.

3. The temperature control method as described in claim 2, characterized in that, The calculation of the specific calorific value of each raw material in the tobacco formulation includes: Control the steam flow rate to ensure a stable input; Each raw material is individually fed into the rehumidifier; The outlet temperature of each raw material output from the rehumidifier is statistically analyzed. The specific heat value of each raw material is calculated based on the outlet temperature, the steam flow rate, and the second functional relationship.

4. The temperature control method as described in claim 2, characterized in that, The calculation of the specific calorific value of each raw material in the tobacco formulation includes: The steam flow rate is controlled to ensure a stable input, and each raw material is sequentially fed into the rehumidifier. The outlet temperature was statistically analyzed, and a curve showing the change of the outlet temperature over time was plotted. The specific heat value of each raw material is calculated based on the curve and the steam flow rate.

5. The temperature control method as described in claim 4, characterized in that, The content of each raw material in the formula is equal, and the specific heat value of each raw material is calculated based on the curve and the steam flow rate, including: The graph is divided into multiple intervals in chronological order, and the number of intervals is equal to the number of raw materials. Calculate the average value of the outlet temperature within each interval, and the average value is regarded as the outlet temperature corresponding to each raw material; The specific heat value of each raw material is calculated based on the outlet temperature, the steam flow rate, and the second functional relationship.

6. The temperature control method according to any one of claims 1 to 5, characterized in that, The first functional relationship is: Wherein, C is the specific heat value, q is the target steam flow rate, η is the steam heat utilization rate, M is the raw material flow rate, t is the preset outlet temperature, t0 is the initial temperature of the raw material, and a is the energy density of the steam.

7. The temperature control method as described in claim 3 or 5, characterized in that, The second functional relationship is: Wherein, C is the specific heat value, Q is the steam flow rate, η is the steam heat utilization rate, M is the raw material flow rate, T is the outlet temperature, T0 is the initial temperature of the raw material, and a is the energy density of the steam.

8. The temperature control method as described in claim 7, characterized in that, The flow rate and weight of each raw material output by the rehumidifier are constant values. The rehumidifier can adjust the steam flow rate to the target steam flow rate corresponding to the raw material at fixed intervals.

9. The temperature control method as described in claim 8, characterized in that, The fixed duration is the ratio of the weight to the flow rate of each raw material.

10. The temperature control method as described in claim 9, characterized in that, The rehumidifier is equipped with a steam outlet for supplying high-temperature steam into the rehumidifier. When each raw material reaches the steam outlet, the steam flow rate is adjusted to the target steam flow rate corresponding to that raw material.

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