Moisture determination method and dehydration system using same

Abstract

The invention discloses a moisture determination method and a dehydration system applying the method, and belongs to the technical field of new materials.The moisture determination method comprises the steps that microwave heating experiments are conducted on a plurality of standard samples with known moisture, and a heating rate-moisture content relation curve of a material is obtained through fitting; and sampling in production, and inquiring the relation curve by using the heating rate data of the sample to indirectly obtain the moisture content of the sample. According to the method, the sample does not need to be completely dried to constant weight, the detection time is shortened, the heating rate is easy to measure, and interference factors are few, so that the moisture determination is rapid and accurate, the technical problem that the detection time is too long is solved, and online analysis conditions are provided for industrial production; in industrial production, the moisture content of a sample can be compared with a target value, and the feeding amount, and / or fuel supply, and / or cold air mixing amount can be adjusted according to a comparison result; the method is used for realizing online detection and timely feedback and improving the product quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to a moisture determination method and a dehydration system applying the method. Background Art

[0002] Laterite nickel ore can produce intermediate products such as nickel oxide, nickel sulfide, and ferronickel. Among them, nickel sulfide and nickel oxide can be used by nickel refineries to solve the problem of insufficient sulfide nickel raw materials.

[0003] Currently, the main process for producing matte nickel from nickel ore is as follows: nickel ore is first smelted to produce low-nickel matte, and then the low-nickel matte is blown to produce matte nickel; in addition, the crushed laterite nickel ore is mixed with a reducing agent to form pellets, and a self-reduced product is obtained under a protective atmosphere. The self-reduced product is selectively oxidized in a weakly oxidizing atmosphere to obtain an oxidized product. After the oxidized product is melted and separated, the metal and gangue are separated to obtain a high-grade nickel-iron alloy; this method is used to produce high-grade nickel-iron alloy products with a nickel content of 30%.

[0004] Among them, in the raw material treatment stage, according to process requirements, the powder of laterite nickel ore (with a free water content of about 1%, a crystal water content of 9% - 10%, and a 200-mesh sieve residue of 30%) needs to be dried into a calcined material. The free water in the calcined material must be completely removed, and the crystal water content is required to be controlled at about 3%. The moisture content cannot fluctuate too much, otherwise it will affect the next batching and smelting quality; therefore, during the drying process, it is necessary to timely know the moisture content of the intermediate product to guide production.

[0005] Chinese Patent CN210154976U discloses a new type of rapid moisture analyzer, which includes an equipment housing, a sealing cover plate, a microwave generator, and an annular heater; the object to be detected is placed on the loading tray, the sealing cover plate is sealed with the equipment housing, and then the annular heater and the microwave generator are turned on through the control system. The annular heater heats the object to be detected from the outside, and the microwave generator makes the object to be detected heat simultaneously inside. The weighing sensor detects the weight change of the object to be detected during the heating process and then sends the detection result to the central processor, and after data processing, it is displayed; the temperature sensor real-time detects the temperature change in the heating chamber, adjusts the working states of the annular heater and the microwave generator in real time, and at the same time transfers the excess heat in the heating chamber to the upper part of the sealing cover plate through the conduction layer, and absorbs the heat through the cooling circulation pipe to prevent the temperature in the heating chamber from being too high and causing damage to the equipment.

[0006] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following defects in the prior art: traditional moisture analyzers generally use the drying and weighing method. The instruments using this method need to heat and dry the sample to a constant weight state, which takes a long time, mostly 1 - 3 hours.

[0007] Although traditional moisture analyzers have high detection accuracy, they are time-consuming, energy-consuming, and inefficient. They can only be used in ordinary laboratories and cannot achieve rapid on-line detection. Therefore, they cannot meet the requirements of on-line analysis. Therefore, there is an urgent need to provide a moisture measurement method and a dehydration system using this method to solve the technical problem of long detection time in the prior art. Summary of the Invention

[0008] To solve the technical problems existing in the prior art, the present invention provides a moisture measurement method and a dehydration system using this method to achieve on-line detection, eliminate delay, provide timely feedback, and improve product quality.

[0009] The present invention provides a moisture measurement method, which includes the following steps:

[0010] Preparation work:

[0011] Make a plurality of standard samples with different moisture contents. The moisture content refers to the water content, and the water includes free water and / or crystal water;

[0012] Conduct microwave heating experiments. The heating intensity and heating time of each standard sample are the same. Collect the temperature difference before and after heating of each standard sample to obtain the heating rate data of each standard sample, including dividing the temperature difference before and after heating by the heating time to obtain the heating rate data of each standard sample. The heating time is set according to actual needs;

[0013] Use the heating rate data of the standard sample and the moisture content to obtain the heating rate - moisture content relationship curve by fitting;

[0014] The above preparation work is to obtain the heating rate - moisture content relationship curve. For the same test variety, the preparation work is only carried out once;

[0015] Moisture measurement process:

[0016] Sample the test sample during the production process. Under the same experimental conditions as the preparation work, obtain the heating rate data of the test sample; use the heating rate data of the test sample to query the heating rate - moisture content relationship curve to obtain the moisture content data of the test sample.

[0017] Preferably, after obtaining the moisture content data of the test sample, compare the moisture content data of the test sample with the target value. According to the comparison result, timely adjust the feeding amount, and / or fuel supply, and / or cold air incorporation amount of the production to achieve on-line detection and improve product quality.

[0018] Preferably, the moisture measurement method further includes: automatically sampling, analyzing, and comparing after adjustment, and automatically issuing an adjustment instruction to achieve closed-loop feedback control.

[0019] The present invention also provides a dehydration system applying the above moisture measurement method. The dehydration system includes a main machine, which is a vertical drying furnace, or a rotary dryer, or a drying hammer crusher, or a vertical mill, or a rotary kiln; and the dehydration system is used for the drying operation of wet materials.

[0020] Preferably, when the main machine of the dehydration system is a vertical drying furnace, the dehydration system includes a moisture detection device and a vertical drying furnace, wherein,

[0021] The vertical drying furnace includes a hot blast stove, a drying furnace body and a separator; the hot blast stove is connected to the drying furnace body, the hot blast stove is equipped with a burner, and the burner is connected to a primary air blower; a cold air valve and a slag discharge port are connected to the bottom of the drying furnace body; a constriction is provided in the middle of the drying furnace body; the top of the drying furnace body is connected to the separator through an air duct;

[0022] The wet materials are fed into the drying furnace body after being metered by a feeding device; the burner uses the combustion of fuel to provide heat source for system dehydration; the wet materials meet the hot air from the hot blast stove, and after heat exchange, the wet materials are dehydrated into dried materials, and the dried materials are discharged after gas-solid separation by the separator and transported to the next process section by a conveying device; wherein, a sampler is connected to the bottom of the separator, and samples are taken through the sampler for moisture detection;

[0023] The moisture detection device includes a heating device, a temperature measuring device, a processing module and an adjusting module; the heating device heats the separated solid materials, the processing module obtains the heating rate of the solid materials according to the temperature of the solid materials measured by the temperature measuring device, detects the moisture content by querying the heating rate - moisture content relationship curve, and compares it with a set value. The adjusting module adjusts the opening degree of the cold air valve according to the comparison result of the processing module; and / or adjusts the supply amount of the wet materials or the fuel, wherein the fuel is solid fuel and / or liquid fuel, for realizing on-line detection, rapid adjustment and ensuring product quality.

[0024] Preferably, the outer shells of the hot blast stove and the drying furnace body are both welded by steel plates and lined with refractory materials.

[0025] Preferably, the burner is also equipped with a secondary air blower connected thereto.

[0026] Preferably, the temperature measuring device selects an infrared temperature sensor.

[0027] Preferably, when the main machine of the dehydration system is a rotary dryer, the dehydration system includes a moisture detection device, a rotary dryer and an annular track, wherein,

[0028] A metering device is connected to the feed end of the rotary dryer. After metering the wet materials through the metering device, they are fed into the rotary dryer. A hot air duct is connected to the feed end of the rotary dryer, and a hot air valve is installed on the hot air duct. The rotary dryer is equipped with lifting plates on the inner wall of its cylinder. The wet materials are gradually dehydrated through heat exchange and finally discharged from the discharge end of the rotary dryer. A conveyor is connected to the discharge end of the rotary dryer, and the dried materials are transported to the next process section by using the conveyor.

[0029] The moisture detection device includes a heating device, a temperature measuring device, a processing module, and an adjustment module. The moisture detection device is placed in a loading tool, and by using the loading tool, the moisture detection device can move reciprocally along a circular track. At the start of the detection, the moisture detection device runs in the same direction as the conveyor and remains relatively stationary with respect to it. The heating device uses microwaves to irradiate a certain area of the discharged materials on the conveyor for a fixed time for heating. The discharged materials are the dried materials. The temperature measuring device is used to collect the temperatures of the discharged materials before and after the test. Then, through calculation by the processing module, the heating rate of the discharged materials is obtained. By querying the relationship curve between the heating rate and the moisture content, the moisture data of the discharged materials are obtained and compared with the set value. And, according to the comparison result of the processing module, an adjustment instruction is issued through the adjustment module. The adjustment methods include: adjusting the feeding amount of the system and / or the hot air supply amount. At the end of the detection, the moisture detection device returns or bypasses the circular track and returns to the initial position. The next detection can be carried out at any time as needed.

[0030] Preferably, the metering device includes an electronic belt scale, and the electronic belt scale is equipped with a weighing sensor and a speed sensor.

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

[0032] The microwave heating technology is different from the traditional heating method. It makes the temperature of the heated material rise by generating "internal frictional heat" through the high-frequency reciprocating movement of dipole molecules inside the heated body. Without any heat conduction process, it can heat the inside and outside of the material simultaneously and raise the temperature at the same time. The heating speed is fast and uniform, and only one fraction or one tenth or several tenths of the energy consumption of the traditional heating method is required to achieve the heating purpose.

[0033] Theoretically analyzed, the amount of heat generated by a substance in a microwave field is closely related to the type of the substance and its dielectric properties, that is, microwaves have the characteristic of selective heating on substances. The heat generated by microwave heating is closely related to the loss of the heated object; the dielectric constants of various dielectrics are usually in the range of 0.0001 to 0.5, so the ability of various objects to absorb microwaves varies greatly; that is to say, dielectrics with large dielectric constants are easily heated by microwaves, while dielectrics with too small dielectric constants are difficult to be heated by microwaves, which is the characteristic of selective heating of microwaves on objects. When using microwaves to heat a moist material, the part with more moisture will be quickly heated because its loss coefficient is large, and then other parts will be gradually heated; among them, the moisture in the sample includes free water, crystal water, etc., that is to say, microwave heating only focuses on the number of hydrogen nuclei contained in the material and has nothing to do with the state of water molecules; according to this characteristic, the more moisture in the sample, the more intense the high-frequency reciprocating motion of water molecules, and the greater the heat generated by microwave heating. The heat makes the sample heat up, resulting in a faster heating rate of the sample. It can be concluded from this that when using microwave to heat a material, the microwave heating rate is proportional to the moisture content of the material per unit mass; that is, within the same heating time, the greater the moisture content of the material, the faster its temperature rises. Accordingly, the present invention utilizes the measurement of the heating rate and can quickly obtain the moisture content of the material through fitting, achieving the invention purpose.

[0034] Then, by using the moisture content of the material, the drying effect can be determined, and based on the drying effect, the feeding amount or fuel supply can be adjusted; further, an automatic closed-loop control is formed to achieve rapid feedback.

[0035] In summary, the moisture measurement result of the present invention is fast and accurate, solving the technical problem of too long detection time and meeting the conditions for on-line analysis. Then, why can't the prior art achieve the above beneficial effects? The reason lies in that

[0036] (1) Traditional moisture meters generally adopt the drying and weighing method (drying loss method), which takes a long time. If on-line measurement of moisture is required, it is obvious that the drying loss method cannot be used anymore. Different from the traditional method, the present invention does not need to completely dry the moisture of the material; therefore, the present invention shortens the detection time, and the measurement of temperature difference is also relatively fast, so the result can be obtained quickly.

[0037] (2)In related technologies, for example, in the grain drying industry, there is also a need for on-line moisture measurement. Usually, moisture is converted into electricity for measurement. Since the 1950s, explorations in this area have been carried out at home and abroad. The earliest attempt was the so-called resistance method, that is, using the relationship between the resistivity of the measured grain itself and moisture to measure the moisture of the grain. Due to low accuracy, it has not been widely used. Subsequently, the capacitance method and the microwave absorption method were developed respectively, and further the γ-ray absorption method was developed. The basic principle of all these methods is to measure moisture through the correlation between the moisture of the measured grain and a certain parameter of it, such as resistivity, dielectric constant or absorption rate. However, the problem is that these parameters are related not only to the moisture of the measured medium, but also to many other factors, such as the temperature, composition, structure and even geometric size of the measured medium. For granular grains, it is also related to the size and compactness of the grains. For example, the microwave absorption moisture meter in related technologies uses the microwave penetration method to realize moisture monitoring. When microwaves pass through the water-containing material and the dry material, the propagation speed and intensity of the microwaves in the propagation direction will change differently. The water-containing material will slow down the propagation speed and weaken the intensity of the microwaves. The microwave absorption moisture meter calculates the moisture content in the material by detecting these two physical property changes of the microwaves after passing through the material. When the thickness and density of the material layer change, the obtained data is inaccurate.

[0038] However, the present invention uses microwave to heat the material and measures the moisture of the material by using the relationship between the moisture content of the measured material and its heating rate. The heating rate is easy to measure and there are fewer interference factors. Therefore, the measurement of the present invention is fast and the result is accurate. It can also be seen from this that compared with the prior art, a moisture measurement method and a dehydration system applying this method provided by the present invention belong to new methods and devices. Using microwave irradiation technology to heat the material, the heating rate of the material is related to its moisture content. For those of ordinary skill in the art, they need to master this rule before they can make improvements to the prior art. However, it is difficult for those skilled in the art to master the said rule. Therefore, the above improvements are obviously more difficult. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of the relationship curve between the heating rate of the material and its moisture content in Embodiment 1 of the present invention;

[0040] Figure 2 is a working flowchart of the dehydration system in Embodiment 2 of the present invention;

[0041] Figure 3 is an assembly schematic diagram of the moisture detection device in Embodiment 2 of the present invention;

[0042] Figure 4 is a working flowchart of the dehydration system in Embodiment 3 of the present invention.

[0043] In the figure:

[0044] 1 - Moisture detection device;

[0045] 11 - Heating device; 12 - Temperature measurement device; 13 - Processing module; 14 - Adjustment module; 15 - Loading tool; 16 - Ring track;

[0046] 2 - Vertical drying furnace;

[0047] 21 - Hot air furnace; 211 - Burner;

[0048] 22 - Drying furnace body; 221 - Shrinkage opening; 222 - Cold air valve; 223 - Slag discharge port; 224 - Feeding device;

[0049] 23 - Separator; 231 - Sampler; 232 - Conveying device;

[0050] 3 - Rotary dryer; 31 - Metering device; 32 - Hot air valve; 33 - Conveyor. Specific implementation mode

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] The present invention provides a moisture measurement method, including the following steps:

[0053] Preparation work:

[0054] Make multiple standard samples with different moisture contents. The moisture content refers to the water content, and the water includes free water and / or crystal water;

[0055] Conduct microwave heating experiments. The heating intensity and heating time of each standard sample are the same. Collect the temperature difference before and after heating of each standard sample to obtain the heating rate data of each standard sample, including dividing the temperature difference before and after heating by the heating time to obtain the heating rate data of each standard sample, and the heating time is set according to actual needs;

[0056] Utilize the heating rate data of the standard samples and the moisture content to obtain the heating rate - moisture content relationship curve by fitting;

[0057] The above preparation work is to obtain the heating rate - moisture content relationship curve. For the same test variety, the preparation work is only carried out once;

[0058] Moisture measurement process:

[0059] During the production process, a test sample is obtained through sampling. Under the same experimental conditions as the preparatory work, the heating rate data of the test sample is obtained. The moisture content data of the test sample is obtained by querying the heating rate - moisture content relationship curve using the heating rate data of the test sample.

[0060] Furthermore, after obtaining the moisture content data of the test sample, the moisture content data of the test sample is compared with the target value. According to the comparison result, the feeding amount of production, and / or the fuel supply, and / or the amount of cold air incorporated are adjusted in a timely manner to achieve on-line detection and improve the product quality.

[0061] Furthermore, the moisture measurement method further includes: after adjustment, automatic sampling, analysis, comparison are performed, and an adjustment instruction is automatically issued to achieve closed-loop feedback control.

[0062] The present invention also provides a dehydration system applying the above moisture measurement method. The dehydration system includes a main machine, and the main machine is a vertical drying furnace 2, or a rotary dryer 3, or a drying hammer crusher, or a vertical mill, or a rotary kiln; the dehydration system is used for the drying operation of wet materials.

[0063] Furthermore, when the main machine of the dehydration system is a vertical drying furnace 2, the dehydration system includes a moisture detection device 1 and a vertical drying furnace 2, wherein,

[0064] The vertical drying furnace 2 includes a hot blast stove 21, a drying furnace body 22 and a separator 23; the hot blast stove 21 is connected to the drying furnace body 22, the hot blast stove 21 is equipped with a burner 211, and the burner 211 is connected to a primary air blower; the bottom of the drying furnace body 22 is connected with a cold air valve 222 and a slag discharge port 223; a constriction 221 is arranged in the middle of the drying furnace body 22; the top of the drying furnace body 22 is connected to the separator 23 through an air duct;

[0065] The wet materials are fed into the drying furnace body 22 after being metered by a feeding device 224; the burner 211 uses the combustion of fuel to provide heat source for the dehydration of the system; the wet materials meet the hot air from the hot blast stove 21, and after heat exchange, the wet materials are dehydrated into dried materials after drying, and the dried materials are discharged after gas-solid separation by the separator 23 and transported to the next process by a conveying device 232; wherein, a sampler 231 is connected to the bottom of the separator 23, and sampling is performed through the sampler 231 for moisture detection;

[0066] The moisture detection device 1 includes a heating device 11, a temperature measuring device 12, a processing module 13, and an adjustment module 14. The heating device 11 heats the separated solid material. The processing module 13 obtains the heating rate of the solid material according to the temperature of the solid material measured by the temperature measuring device 12, detects the moisture content by querying the heating rate - moisture content relationship curve, and compares it with a set value. The adjustment module 14 adjusts the opening degree of the cold air valve 222 according to the comparison result of the processing module 13; and / or adjusts the supply amount of the wet material or the fuel, where the fuel is a solid fuel and / or a liquid fuel, for realizing on-line detection, rapid adjustment, and ensuring product quality.

[0067] Further, the outer shells of the hot blast stove 21 and the drying furnace body 22 are both welded by steel plates and lined with refractory materials.

[0068] Further, the burner 211 is also equipped with a secondary air blower connected thereto.

[0069] Further, the temperature measuring device 12 selects an infrared temperature sensor.

[0070] Further, when the main machine of the dehydration system is a rotary dryer 3, the dehydration system includes a moisture detection device 1, a rotary dryer 3, and an annular track 16, where

[0071] A metering device 31 is connected to the feeding end of the rotary dryer 3. After the wet material is metered by the metering device 31, it is fed into the rotary dryer 3. A hot air pipeline is connected to the feeding end of the rotary dryer 3, and a hot air valve 32 is installed on the hot air pipeline. The rotary dryer 3 is provided with lifting plates on the inner wall of its cylinder. The wet material is gradually dehydrated through heat exchange and finally discharged from the discharging end of the rotary dryer 3. A conveyor 33 is connected to the discharging end of the rotary dryer 3, and the dried material is transported to the next process section by using the conveyor 33.

[0072] The moisture detection device 1 includes a heating device 11, a temperature measuring device 12, a processing module 13 and an adjustment module 14; the moisture detection device 1 is placed in a loading tool 15, and by using the loading tool 15, the moisture detection device 1 can reciprocate along an annular track 16; at the start of detection, the moisture detection device 1 runs in the same direction as the conveyor 33, and the two maintain relative rest; the heating device 11 uses microwaves to irradiate and heat a certain area of the material exiting the machine on the conveyor 33 at a fixed time, and the material exiting the machine is the dried material; the temperature measuring device 12 is used to collect the temperature of the material exiting the machine before and after the test; then, through calculation by the processing module 13, the heating rate of the material exiting the machine is obtained, and by querying the heating rate - moisture content relationship curve, the moisture data of the material exiting the machine is known and compared with the set value; and, according to the comparison result of the processing module 13, an adjustment instruction is issued through the adjustment module 14; the adjustment method includes: adjusting the feeding amount of the system and / or the hot air supply amount; at the end of detection, the moisture detection device 1 returns or bypasses the annular track 16 and returns to the initial position; as needed, the next detection can be carried out at any time.

[0073] Further, the metering device 31 includes an electronic belt scale, and the electronic belt scale is equipped with a weighing sensor and a speed measuring sensor.

[0074] Embodiment 1

[0075] Refer to Figure 1 , this embodiment provides a moisture determination method, including the following steps:

[0076] Preparation work:

[0077] Step S10, prepare multiple standard samples with different moisture contents, where the moisture content refers to the water content, and the water includes free water and / or crystal water; as needed, the moisture content of the standard samples can start from 0% and increase in increments of 0.2% or 0.5%; alternatively, water can be added or samples can be selected at will, and other methods can be used to detect the moisture, but it is necessary to ensure that the detection results of the moisture content are accurate; for the sake of easy understanding, in this embodiment, Figure 1 the moisture content increases in increments of 1%.

[0078] Step S20, conduct microwave heating experiments. The heating intensity and heating time of each standard sample are the same, set to 30 seconds in this embodiment, and an infrared temperature measuring instrument is used to collect temperature data; then, divide the temperature difference before and after heating by the time to obtain the heating rate data of each standard sample.

[0079] Step S30, using the heating rate data and the moisture content, draw / fit a heating rate-moisture content relationship curve. The more data there is, the smoother and more accurate the relationship curve will be. The fitting is to find a function curve that fits the experimental measurement data points as closely as possible. Since there are various forms of functions, there are various fitting methods. The fitted curve can generally be represented by a function, and there are different fitting names based on the difference in this function, such as linear fitting, cubic spline curve fitting, etc. The above is the preparatory work. It can be understood that the preparatory work is one-time and will not be performed again when analyzing the sample unless the test variety is changed. See Figure 1 , Figure 1 A schematic diagram of the relationship between the heating rate of a given material and its moisture content is given, such as Figure 1 As shown:

[0080] The vertical axis is the heating rate △T / t, which is expressed as ℃ / s, where △T=T2-T1, T1 is the initial temperature of the material. In industrial production, since the material has just been discharged from the dehydration system, this temperature will obviously be higher than the ambient temperature; T2 is the temperature at the end of microwave heating; by collecting the temperature difference, the influence of the ambient temperature on the measurement result is reduced; t is the heating time, which is constant and can be set as needed. In this embodiment, it is measured in seconds and can be realized by a timer;

[0081] The horizontal axis is the mass percentage of the initial moisture content of the material, calculated as W%. The initial moisture content refers to the residual moisture content of the material after industrial dehydration, that is, the moisture content of the intermediate product. The initial moisture content (residual moisture content) is not the initial moisture content of the raw material. After the microwave heating test, a portion of the residual moisture content will further evaporate. However, the present invention does not need to know the final moisture content. Therefore, the moisture determination method of the present invention does not need to heat the sample to dehydrate to constant weight, so the test is fast.

[0082] By observing the heating rate-moisture content relationship curve, it can be found that the greater the moisture content of the material, the faster the heating rate; the curve is different with different material types and heating conditions, and the only constant is that the curve increases monotonically with moisture; the more data, the higher the accuracy, but it cannot change its essence, which is understandable; Example 1 is fully sufficient as a production aid.

[0083] Moisture determination process:

[0084] Step S40: In this step, sampling is performed during the industrial production process, and the obtained sample is a test sample; and under the same experimental conditions as the preparation work, similar to step S20, the heating rate data of the test sample is obtained.

[0085] Step S50, using the heating rate data of the sample to query the relationship curve, to obtain the moisture content data of the sample; for example,Figure 1 As shown, the heating rate of the sample is 8.8 °C / s. By querying the relationship curve, it can be known that the moisture content of the sample is 2.7%.

[0086] So far, through the above steps, as a moisture measurement method, this embodiment has completed the task. It can be seen that in the moisture measurement method of the present invention, although the acquisition of the relationship curve is relatively troublesome, it is a one-time preparatory work; in the sample analysis stage, the analysis results are obtained quickly and accurately, which is also a necessary prerequisite for realizing on-line detection.

[0087] In other embodiments, step S60 may further be included. After obtaining the moisture content data of the sample, the moisture content data of the sample is compared with a target value, which is also a set value. According to the comparison result, the feeding amount of industrial production, and / or the fuel supply, and / or the cold air incorporation amount are adjusted in a timely manner; through this step, on-line detection can be realized and the product quality can be improved.

[0088] Furthermore, in other embodiments, step S60 further includes: automatically sampling, automatically analyzing, and automatically issuing an adjustment instruction according to the comparison result for realizing cyclic repeated detection and automatic feedback.

[0089] Embodiment 2

[0090] In industrial production, dehydration systems are often used for the drying operation of wet materials. There are many types of main machines for the dehydration system, such as drying hammer crushers, vertical mills, rotary kilns, vertical drying furnaces 2 or rotary dryers 3, etc.; among them,

[0091] The drying hammer crusher, also known as the drying hammer breaker, is used to crush and dry soft and non-abrasive materials such as gypsum, chalk, clay, slurry filter cakes, etc. It has the functions of dispersing and crushing while drying. The rotating rotor disperses the material, the hot air dries the material, and the air flow takes the crushed and dried material to the separation chamber. The fine powder then enters the cyclone for separation, and the coarse particles return to the hammer crusher for re-crushing.

[0092] The vertical mill uses grinding rollers to extrude the material on the grinding table and relies on the air flow to carry out of the mill the particles that meet the fineness requirements, which are collected by the dust collector to become the finished product; inside the vertical mill, the particles with larger particle sizes in the air flow fall back to the grinding table for grinding under the action of gravity. This process needs to be carried out multiple times to make its fineness meet the requirements; as a drying and grinding machine, during the grinding process of the vertical mill, heat exchange occurs through the contact of gas and solid, and the wet material is dried. The thermal efficiency of drying using the vertical mill is relatively high.

[0093] Regarding the application of the above moisture measurement method in industrial production, this embodiment gives multiple specific solutions, which can be selected according to actual needs.

[0094] Refer to Figure 1 、and Figure 2 and Figure 3 , this embodiment provides a dehydration system applying the above moisture measurement method. The main machine of the dehydration system is a vertical drying furnace 2. The dehydration system includes a moisture detection device 1 and a vertical drying furnace 2. Among them,

[0095] The vertical drying furnace 2 includes a hot blast stove 21, a drying furnace body 22 and a separator 23; In this embodiment, the outer shells of the hot blast stove 21 and the drying furnace body 22 are both welded by steel plates and lined with refractory materials;

[0096] The hot blast stove 21 is connected to the drying furnace body 22. The hot blast stove 21 is equipped with a burner 211, and the burner 211 is equipped with a primary air blower; In other embodiments, the burner 211 is also equipped with a secondary air blower; Burners are widely used in industrial kilns such as boilers, precalcining furnaces, heating furnaces, rotary kilns, etc. It is the core combustion equipment of industrial kilns. Its function is to make the fuel burn preliminarily under the transportation and combustion support of the primary air; This embodiment is provided with a primary air blower. The outlet of the primary air blower is connected to the burner through a primary air duct. Fuel is fed into the front end of the primary air duct, and then the air flow generated by the primary air blower carries the fuel, passes through the burner, and sprays the fuel into the furnace chamber of the hot blast stove 21. The air flow is the primary air for fuel combustion. Further, a secondary air blower can be added. The outlet of the secondary air blower is also connected to the burner through a secondary air duct. The secondary air blower inhales fresh air to provide secondary air for assisting fuel combustion; That is to say, the fuel can burn fully and release heat under the combustion support of the secondary air.

[0097] The bottom of the drying furnace body 22 is connected with a cold air valve 222 and a slag discharge port 223; The cold air valve 222 can adjust the hot air temperature by adjusting the air intake amount.

[0098] The wet material is fed into the drying furnace body 22 after being metered by a feeding device 224; The burner 211 uses the combustion of fuel to provide heat source for system dehydration; The wet material meets the hot air from the hot blast stove 21 and generates heat exchange; A contraction port 221 is arranged in the middle of the drying furnace body 22. When the air flow passes through the contraction port 221, due to the reduction of the furnace body cross-sectional area, the flow rate increases, which strongly disturbs the material and can produce a spouting effect to enhance the heat exchange effect; After heat exchange, the wet material is dehydrated into dried material and rises along with the air flow; A wind pipe is arranged at the top of the drying furnace body 22 and is connected to the separator 23 through the wind pipe. The dried material completes gas-solid separation through the separator 23 and is discharged, and is transported to the next process section by a conveying device 232;

[0099] In this embodiment, the separator 23 is a cyclone separator, also known as a cyclone dust collector. It is a dry gas-solid separation device that uses the centrifugal force generated when the material makes a high-speed rotational motion to separate dust from the gas stream. Its main structure is a conical cylinder. The upper section of the cylinder is equipped with an inlet pipe along the tangential direction, the top of the cylinder is equipped with an exhaust pipe inserted into the cylinder to a certain depth, and the bottom of the conical cylinder has an ash discharge pipe. The dust-containing gas stream generally enters the cyclone separator from the inlet pipe at a speed of 12 - 30 m / s, and the gas stream changes from a linear motion to a circular motion. The dust particles contained therein are thrown towards the peripheral wall under the action of the centrifugal force. Once the dust particles collide with the peripheral wall, they lose their kinetic energy and slide along the wall surface into the ash discharge pipe, thus separating the gas and solid.

[0100] A sampler 231 is connected to the bottom of the separator 23. Sampling is carried out through the sampler 231, and moisture detection is performed using the moisture detection device 1. Among them,

[0101] Regarding the sampler 231, in this embodiment, a pneumatic airtight sampler is selected to collect relatively dry powder materials or easily flowing samples of round small particles. The pneumatic airtight sampler is installed on the chute of the material transportation, and compressed air is required on-site to drive it, with a pressure of 0.4 - 1.0 MPa. The pneumatic airtight sampler relies on compressed air to push the piston rod of the cylinder to move, thereby driving the piston in the sampling pipe to scrape the material. There is a feed inlet above the sampling pipe. At the sampling time, the piston scrapes the material into the storage bucket. The sampling volume is controlled by a time relay. After sampling, the sample can also be automatically transported to the analysis site, eliminating the step of climbing stairs to get the sample. Therefore, it can save time and reduce labor intensity.

[0102] Microwave refers to electromagnetic waves with frequencies between 300 MHz and 300 GHz. It has the characteristics of being easy to aggregate into a beam, highly directional, and propagating in a straight line. When using microwave heating, under the condition of consistent irradiation intensity, water molecules per unit mass generate heat to heat the sample itself, manifested as an increase in temperature, and the increase amplitude is only related to its specific heat capacity. Specific Heat Capacity, also known as specific heat capacity, is abbreviated as specific heat. It is the heat capacity of a unit mass of a substance, that is, the heat absorbed or released by a unit mass of an object when it changes a unit temperature. Therefore, the moisture determination method of the present invention does not have high requirements for the total weight of the sample, and the test sample does not need to be weighed. For example, measuring cups of the same specification can be used to hold the test sample. After scraping it flat, it can be used for testing.

[0103] Microwaves cannot be used to heat metals. For example, a microwave oven cannot heat metals because metals are conductive. When a metal object is placed in a microwave oven, the microwave radiation generated by the microwave oven will generate an electric current on the metal surface. These electric currents will cause the metal object to heat up. However, due to the very good conductivity of the metal, the electric current will spread rapidly inside the metal, resulting in overheating of the metal. Metal overheating may pose a risk of fire or burns. Therefore, for the part of the temperature measuring element that contacts the microwave, components containing metal materials cannot be used, including resistance thermometers or thermocouple thermometers, such as thermocouples. Regarding the selection of the temperature measuring element, in this embodiment, wireless temperature measurement is adopted, and an infrared temperature sensor, such as an infrared thermometer gun, is selected.

[0104] Refer to Figure 3 , this embodiment provides an assembly schematic diagram of a dehydration system including a moisture detection device 1 and a vertical dryer. The moisture detection device 1 includes a heating device 11, a temperature measuring device 12, a processing module 13, and an adjustment module 14. Each part is detachably connected for convenient maintenance. The heating device 11 heats the separated solid material. The processing module 13 obtains the heating rate of the solid material based on the temperature of the solid material measured by the temperature measuring device 12, detects the moisture content by querying the heating rate - moisture content relationship curve, and compares it with a set value. The adjustment module 14 adjusts the supply amount of the wet material or the fuel according to the comparison result of the processing module 13. The fuel is solid fuel and / or liquid fuel. In addition, the adjustment method can also choose to adjust the opening degree of the cold air valve 222.

[0105] The moisture detection device 1 adopts a self-feedback system, and its working process (principle) specifically includes:

[0106] (1) Use the heating device 11 to perform microwave heating treatment on the sample. Use the temperature measuring device 12 to collect the temperature change of the sample before and after heating, and obtain the heating rate data of the sample. In the processing module 13, there is a heating rate - moisture content relationship curve of the material. Substitute the heating rate data of the sample into it and calculate to obtain the moisture content (moisture) of the sample.

[0107] (2) Use the adjustment module 14 to receive the moisture content (moisture) data of the sample and compare it with a given value (target value), where the given value is preset in advance. If it exceeds the range, an instruction is sent to the actuator, and the actuator includes the feeding equipment of the dehydration system or the adjustment device of the air valve.

[0108] (3) After receiving the instruction, the actuator makes a feedback, which is converted into a standard control signal of DC 4-20 mA by the intelligent PID regulator to adjust the feeding amount of the feeding device 224 or the opening degree of the cold air valve 222. By adjusting the supply balance of the wet material and the hot air, the controlled process parameter (the moisture content of the product) is maintained at a given value, realizing automatic PID regulation and control.

[0109] For example, when the analysis result shows that the moisture content of the material is too high and exceeds the set value, the system issues an instruction to the feeding device 224 through the adjustment module 14 to reduce the feeding of the wet material. After the wet material is reduced, the hot air is sufficient, and the moisture of the product out of the machine is thus reduced; or, by controlling the burner 211, the supply of fuel is increased to make up for the shortage of system heat, and the same effect can also be achieved; at that time, an audible and visual alarm signal can also be issued; by using the above technical means, precise control of the moisture of the product of the dehydration system is realized.

[0110] In summary, the embodiment of the present invention realizes on-line detection, facilitates quick adjustment, and ensures product quality.

[0111] Embodiment 3

[0112] Refer to Figure 1 、 Figure 3 and Figure 4 In addition, this embodiment also provides another dehydration system applying the above moisture measurement method. The main machine of the dehydration system is a rotary dryer 3. The dehydration system includes a moisture detection device 1, a rotary dryer 3, and a loading tool 15. On the basis of Embodiment 2, the difference in this embodiment is that (1) this embodiment uses a rotary dryer for drying operations; (2) the moisture detection device 1 is movable.

[0113] A metering device 31 is connected to the feeding end of the rotary dryer 3. After the wet material is metered by the metering device 31, it is fed into the rotary dryer 3; a hot air pipeline is connected to the feeding end of the rotary dryer 3, and a hot air valve 32 is installed on the hot air pipeline. The hot air valve 32 is used to adjust the supply amount of hot air; the rotary dryer 3 is provided with lifting plates on the inner wall of its cylinder; the discharging end of the rotary dryer 3 is connected to a conveyor 33, and the dried material is conveyed to the next process section by using the conveyor 33;

[0114] In this embodiment, the wet material enters the dryer through the metering device 31. Since its cylinder body makes a slow rotary motion in an inclined state, the material moves from the high end to the low end in the axial direction. During the movement, the lifting plates lift, scatter and move the material downward in the circumferential direction, so that the material can fully exchange heat with the air until it is dried to below the specified moisture content. That is to say, through heat exchange, the wet material is gradually dehydrated. Finally, the dried material is discharged from the discharge end of the rotary dryer 3. Among them,

[0115] The metering device 31 can adopt an electronic belt scale. The electronic belt scale is an electronic metering device that, based on a belt conveyor, uses a matching structure to assemble a weighing bridge (referred to as a scale bridge) in the belt conveyor to continuously weigh and measure bulk materials. Among them, a weighing sensor is installed on the weighing bridge of the electronic belt scale to detect the material weight signal on the belt. During operation, the weight signal is sent to a weighing instrument. At the same time, a speed sensor senses the speed signal of the belt and also sends it to the weighing instrument. The weighing instrument integrates the speed signal and the weight signal to obtain the instantaneous flow rate and the cumulative amount.

[0116] The moisture detection device 1 includes a heating device 11, a temperature measuring device 12, a processing module 13 and an adjustment module 14. The moisture detection device 1 is placed in a loading tool 15. By using the loading tool 15, the moisture detection device 1 can reciprocate along a circular track 16.

[0117] At the start of detection, the moisture detection device 1 runs in the same direction as the conveyor 33 and at the same running speed, that is, they remain relatively stationary to each other. The heating device 11 uses microwaves to irradiate a certain area of the material discharged from the machine on the conveyor 33 for a fixed time. The material discharged from the machine is the dried material. It is possible to set the temperature measurement point to automatically follow the center of the microwave irradiation, and use the temperature measuring device 12 to collect the temperature of the material discharged from the machine before and after the test. Then, through calculation by the processing module 13, the heating rate of the material discharged from the machine is obtained. By querying the fitting curve, the moisture data of the material discharged from the machine can be obtained and compared with the set value, which is input in advance. And, according to the comparison result, an adjustment instruction is issued through the adjustment module 14. The adjustment methods include: adjusting the feeding amount of the system and / or the hot air supply amount. At the end of the detection, the moisture detection device 1 returns or bypasses to the initial position and can be used for the next detection at any time as needed.

[0118] That is to say, at the beginning of the test, the microwave heating device, the temperature measuring device and the material conveying device are synchronized, that is, they move a certain distance following the material conveying device, remain relatively stationary with the material, and maintain for a period of time; the temperature is measured at the beginning and end of the test respectively, and the temperature difference is divided by the heating time to obtain the heating rate data of the material; then the synchronization is released and the initial position is returned to prepare for the next test work.

[0119] In summary, through the above steps, the present invention can timely feedback moisture; taking the drying of grains as an example, it can prevent "under-drying", and "under-drying" will lead to excessive moisture in grains, easy mildew, and unqualified quality; it can also prevent "over-drying". Grains are purchased by the granary at a cost. If they are dried too dry, the fresh grains will lose too much weight, resulting in losses in inventory counting and losses to the granary. In addition, this embodiment realizes sampling-free analysis.

[0120] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A moisture determination method, characterized in that, It includes the following steps: Preparation work: Make multiple standard samples with different moisture contents. The moisture content refers to the water content, and the water includes free water and / or crystal water; Conduct microwave heating experiments. The heating intensity and heating time of each standard sample are the same. Collect the temperature difference before and after heating of each standard sample to obtain the heating rate data of each standard sample, including dividing the temperature difference before and after heating by the heating time to obtain the heating rate data of each standard sample, and the heating time is set according to actual needs; Use the heating rate data of the standard samples and the moisture content to obtain the heating rate - moisture content relationship curve through fitting; The above preparation work is to obtain the heating rate - moisture content relationship curve. For the same test variety, the preparation work is only carried out once; Moisture determination process: Sample the test sample during the production process. Under the same experimental conditions as the preparation work, obtain the heating rate data of the test sample; use the heating rate data of the test sample to query the heating rate - moisture content relationship curve to obtain the moisture content data of the test sample.

2. The moisture determination method according to claim 1, wherein After obtaining the moisture content data of the test sample, compare the moisture content data of the test sample with the target value. According to the comparison result, timely adjust the feeding amount, and / or fuel supply, and / or cold air incorporation amount of production.

3. The moisture measurement method according to claim 2, wherein The moisture determination method further includes: after adjustment, conduct automatic sampling, analysis, and comparison, and automatically issue an adjustment instruction to achieve closed-loop feedback control.

4. A dehydration system applying the moisture measurement method according to any one of claims 1-3, characterized in that, The dehydration system includes a main machine, and the main machine is a vertical drying furnace (2), or a rotary dryer (3), or a drying hammer crusher, or a vertical mill, or a rotary kiln; the dehydration system is used for the drying operation of wet materials.

5. The dehydration system according to claim 4, wherein When the main machine of the dehydration system is a vertical drying furnace (2), the dehydration system includes a moisture detection device (1) and a vertical drying furnace (2), where The vertical drying furnace (2) includes a hot blast stove (21), a drying furnace body (22), and a separator (23); the hot blast stove (21) is connected to the drying furnace body (22), the hot blast stove (21) is equipped with a burner (211), and the burner (211) is connected to a primary air blower; the bottom of the drying furnace body (22) is connected with a cold air valve (222) and a slag discharge port (223); a constriction (221) is arranged in the middle of the drying furnace body (22); the top of the drying furnace body (22) is connected to the separator (23) through an air duct; The wet material is metered by a feeding device (224) and then fed into the drying furnace body (22); the burner (211) uses the combustion of fuel to provide heat for the dehydration of the system; the wet material meets the hot air from the hot blast stove (21), and after heat exchange, the wet material is dehydrated into a dried material. The dried material is discharged after gas-solid separation by the separator (23) and is transported to the next process by a conveying device (232); among them, a sampler (231) is connected to the bottom of the separator (23), and sampling is carried out through the sampler (231) for moisture detection; The moisture detection device (1) includes a heating device (11), a temperature measuring device (12), a processing module (13), and an adjustment module (14); the heating device (11) heats the separated solid material, and the processing module (13) obtains the heating rate of the solid material according to the temperature of the solid material measured by the temperature measuring device (12), detects the moisture content by querying the heating rate - moisture content relationship curve, and compares it with a set value. The adjustment module (14) adjusts the opening degree of the cold air valve (222) according to the comparison result of the processing module (13); and / or adjusts the supply amount of the wet material or the fuel, where the fuel is solid fuel and / or liquid fuel.

6. The dehydration system according to claim 5, wherein The outer shells of the hot blast stove (21) and the drying furnace body (22) are both welded by steel plates and lined with refractory materials.

7. The dehydration system according to claim 5, characterized in that, The burner (211) is also equipped with a secondary air blower connected thereto.

8. The dehydration system according to claim 5, wherein The temperature measuring device (12) selects an infrared temperature sensor.

9. The dehydration system according to claim 4, characterized in that, When the main machine of the dehydration system is a rotary dryer (3), the dehydration system includes a moisture detection device (1), a rotary dryer (3), and an annular track (16), where The feeding end of the rotary dryer (3) is connected with a metering device (31), and after the wet material is metered by the metering device (31), it is fed into the rotary dryer (3); the feeding end of the rotary dryer (3) is connected with a hot air pipeline, and a hot air valve (32) is installed on the hot air pipeline; the rotary dryer (3) is provided with lifting plates on the inner wall of its cylinder; the wet material is gradually dehydrated through heat exchange and finally discharged from the discharging end of the rotary dryer (3); the discharging end of the rotary dryer (3) is connected with a conveyor (33), and the dried material is transported to the next process section by using the conveyor (33); The moisture detection device (1) includes a heating device (11), a temperature measuring device (12), a processing module (13), and an adjustment module (14); the moisture detection device (1) is placed in a loading tool (15), and by using the loading tool (15), The moisture detection device (1) can reciprocate along the annular track (16); at the start of detection, the moisture detection device (1) runs in the same direction as the conveyor (33), and the two are relatively stationary; the heating device (11) uses microwaves to irradiate and heat a certain area of the material discharged from the machine on the conveyor (33) at a fixed time, and the material discharged from the machine is the dried material; the temperature measuring device (12) is used to collect the temperature of the material discharged from the machine before and after the test; then, through the calculation of the processing module (13), the heating rate of the material discharged from the machine is obtained, and by querying the heating rate - moisture content relationship curve, the moisture data of the material discharged from the machine is obtained and compared with the set value; and, according to the comparison result of the processing module (13), an adjustment instruction is issued through the adjustment module (14); the adjustment method includes: adjusting the feeding amount of the system and / or the hot air supply amount; at the end of the detection, the moisture detection device (1) returns or bypasses the annular track (16) and returns to the initial position; according to needs, the next detection can be carried out at any time.

10. The dehydration system according to claim 9, wherein, The metering device (31) includes an electronic belt scale, The electronic belt scale is equipped with a weighing sensor and a speed measuring sensor.

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