Preparation process for quickly drying rice

Abstract

The invention relates to a preparation process for quickly drying rice, which comprises the following steps: putting rice to be dried into a drying bin, and setting a first threshold value, a second threshold value and a target water content, the current water content of the rice is periodically obtained; if yes, the rice is rapidly pre-dried at the first temperature through a hot air mechanism; if yes, the rice is subjected to main drying tempering at the second temperature through the hot air mechanism; if yes, the rice is precisely dried and tempered at the third temperature through a hot air mechanism; and n is greater than or equal to 1. Through real-time moisture content monitoring and feedback, the drying process can be dynamically adjusted according to the change of the moisture content of the rice, precise drying of the rice is achieved, excessive drying or insufficient drying is avoided, and the appearance quality and nutrition retention of the rice are improved.

Description

Technical Field

[0001] This invention relates to the field of energy-saving drying technology, and in particular to a preparation process for rapid drying of rice. Background Technology

[0002] Rice is one of the most important staple foods in my country and even the world. After harvesting, paddy contains a high moisture content, and if it is not dried to a safe moisture level in time, it is very prone to mold and sprouting, resulting in huge losses. Traditional natural sun-drying methods are greatly affected by the weather, have a long cycle, require a large area, and are prone to introducing secondary pollution.

[0003] In existing technologies, hot air dryers are mostly used for mechanical drying of paddy rice. To prevent the paddy rice from cracking and affecting the subsequent rice milling quality and head rice yield, the drying temperature is usually controlled at a low level, resulting in slow drying speed and high energy consumption. Furthermore, the drying process is mostly based on fixed time or experience-based judgment, which makes the drying effect unstable for different varieties and initial moisture content of paddy rice, easily leading to over-drying or under-drying, thus affecting the quality of rice.

[0004] Based on the above-mentioned technical problems, this application proposes a preparation process for rapid drying of rice. Summary of the Invention

[0005] The purpose of this invention is to provide a preparation process for rapid drying of rice, in order to solve the technical problems mentioned in the background art. This purpose is achieved through the following technical solution: A preparation process for rapid drying of rice includes the following steps: Step S1. Place the rice to be dried into the drying chamber and set the first threshold. Second threshold and target moisture content ,in, ; Step S2. Periodically obtain the current moisture content of the rice using a moisture content testing agency. The current moisture content With the first threshold Second threshold and target moisture content contrast: like Then, through the hot air mechanism at the first temperature Rapid pre-drying of rice; like Then, through the hot air mechanism at a second temperature The rice undergoes primary drying and tempering processes; like Then, through the hot air mechanism at a third temperature Rice undergoes precise drying and tempering; in, .

[0006] Furthermore, the first threshold The second threshold is 18%-20%. It is 14%-16%.

[0007] Furthermore, in the rapid pre-drying stage, the temperature of the hot air mechanism is 50-70℃, the wind speed is 1.5-2.5m / s, and the time is 10-30min.

[0008] Furthermore, during the main drying and tempering stage, drying and tempering alternate in a cycle. During drying, the temperature of the hot air mechanism is 40-60℃, the wind speed is 1.0-1.5m / s, and the drying time for a single cycle is 8-12min. During tempering, the hot air mechanism stops working, and the tempering time for a single cycle is 8-12min.

[0009] Furthermore, during the precise drying and tempering stage, drying and tempering alternate in a cycle. During drying, the temperature of the hot air mechanism is 30-50℃, the wind speed is 0.5-1.0m / s, and the drying time is 3-5min per cycle. During tempering, the hot air mechanism stops working, and the tempering time is 8-16min per cycle.

[0010] Furthermore, the drying chamber is equipped with a radio frequency heating mechanism. During the tempering process, the radio frequency heating mechanism intermittently applies a radio frequency electric field with a working frequency of 30-50MHz and a power density of 0.5-3 W / kg to the rice.

[0011] Furthermore, a stirring mechanism is installed inside the drying chamber, with a stirring speed of 2-5 rpm.

[0012] Furthermore, step S1 also includes: Step S11. Determine the initial moisture content of the rice to be dried using the oven drying method. ; Step S12. Obtain the second initial moisture content of the rice to be dried using a moisture content testing agency. ; Step S13. Based on the first initial moisture content With the second initial moisture content The difference is used to calibrate the readings of the moisture content testing agency.

[0013] The technical solutions provided in this application have at least the following technical effects or advantages: 1. By monitoring and providing feedback on the real-time moisture content, the drying process can be dynamically adjusted according to changes in the moisture content of the rice, achieving precise drying of the rice, avoiding over-drying or under-drying, and improving the appearance quality and nutrient retention of the rice. 2. By dividing the process into different stages, higher drying temperatures are used when the moisture content is high, which improves drying efficiency; when the moisture content is close to the target value, lower temperature drying and more frequent tempering are used to improve the accuracy and uniformity of drying. 3. By leveraging the deep penetration and uniform heating characteristics of radio frequency, the rice pile is activated from the inside out, significantly accelerating the migration rate of internal moisture to the surface, greatly shortening the tempering time and improving drying efficiency. 4. The initial moisture content was determined by the oven drying method, which enabled the calibration and verification of the moisture content testing agency. This improved the accuracy of moisture content monitoring, thereby improving the accuracy of drying and ensuring the quality of rice. Detailed Implementation

[0014] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0015] A preparation process for rapid drying of rice includes the following steps: Step S1. The rice to be dried is passed through a vibrating screen and an air separator to remove impurities and stones, and then fed into the drying chamber. The first threshold is set. Second threshold and target moisture content ,and .

[0016] Among them, the first threshold The second threshold is 18%-20%. The target moisture content is 14%-16%. for .

[0017] The drying chamber includes a control mechanism, a hot air mechanism, a moisture content detection mechanism, a temperature detection mechanism, a radio frequency heating mechanism, and a stirring mechanism. The hot air mechanism, moisture content detection mechanism, temperature detection mechanism, radio frequency heating mechanism, and stirring mechanism are all electrically connected to the control mechanism via wires. The control mechanism obtains the temperature and moisture content information of the rice from the moisture content detection mechanism and the temperature detection mechanism, and controls the hot air mechanism, radio frequency heating mechanism, and stirring mechanism to execute the corresponding process parameters.

[0018] The moisture content detection mechanism uses a near-infrared sensor or a capacitive sensor to measure the average moisture content of the rice non-contactly and transmit the data to the control mechanism. The temperature detection mechanism uses an infrared sensor to detect the temperature of the drying chamber and the rice.

[0019] Step S11. Randomly select three samples from the rice to be dried, determine the initial moisture content of the rice using the oven drying method, and take the average of the samples to obtain the first initial moisture content of the rice to be dried. ; Step S12. Obtain the second initial moisture content of the rice to be dried using a moisture content testing agency. ; Step S13. Based on the first initial moisture content With the second initial moisture content The difference in readings from the moisture content testing agency is used to calibrate the moisture content. In the formula, The readings are calibrated by the moisture content testing agency. This is the reading before calibration by the moisture content testing agency.

[0020] The initial moisture content was determined by the oven drying method, which enabled the calibration and verification of the moisture content testing agency. This improved the accuracy of moisture content monitoring, thereby improving the accuracy of drying and ensuring the quality of rice.

[0021] Step S2. Periodically obtain the current moisture content of the rice using a moisture content testing device at a sampling frequency of 1 minute / time. The current moisture content With the first threshold Second threshold and target moisture content contrast: like Then, through the hot air mechanism at the first temperature The rice is pre-dried quickly.

[0022] During the rapid pre-drying stage, the temperature of the hot air mechanism is 50-70℃, the air velocity is 1.5-2.5 m / s, and the time is 10-30 minutes. Hot air penetrates the rice layer from the bottom of the drying chamber upwards or horizontally, and the stirring mechanism agitates the rice layer at a speed of 2-5 rpm until the real-time moisture content is reached. Drop to the first threshold During this stage, high-temperature hot air is used to rapidly evaporate and remove free water from the surface of the rice, creating conditions for internal moisture migration and thus improving the drying efficiency of the rice.

[0023] like Then, through the hot air mechanism at a second temperature The rice undergoes primary drying and tempering.

[0024] During the main drying and tempering stage, the stirring mechanism turns the rice layer over at a speed of 2-5 rpm, alternating between drying and tempering until the real-time moisture content is reached. Drop to the second threshold During the drying cycle, the outlet air temperature of the hot air mechanism is 40-60℃, the air velocity is 1.0-1.5m / s, and the drying time for a single cycle is 8-12 minutes. During the tempering cycle, the hot air mechanism stops working, and the radio frequency heating mechanism applies a radio frequency electric field with a working frequency of 30-50MHz and a power density of 0.5-3 W / kg to the rice at a ratio of 1:3 between operation and shutdown time, with a tempering time of 8-12 minutes for a single cycle.

[0025] At this stage, the main function is to drive the internal moisture of the rice to migrate to the surface and to balance the internal and external moisture gradient through tempering, thus preventing cracking. On one hand, hot air drying dries the rice from the outside, creating a humidity gradient on the rice surface; on the other hand, radio frequency tempering heats the rice grains from the inside out, promoting the outward migration of internal moisture. The combined effect of these two processes accelerates the rate of internal moisture migration to the surface, improving drying efficiency.

[0026] like Then, through the hot air mechanism at a third temperature The rice undergoes precise drying and slow ripening.

[0027] During the precise drying and tempering stage, the stirring mechanism agitates the rice layer at a speed of 2-5 rpm, alternating between drying and tempering until the real-time moisture content is reached. Stable achievement of target moisture content During the drying cycle, the outlet air temperature of the hot air mechanism is 30-50℃, the air velocity is 0.5-1.0m / s, and the drying time for a single cycle is 3-5 minutes. During the tempering cycle, the hot air mechanism stops working, and the radio frequency heating mechanism applies a radio frequency electric field with a working frequency of 30-50MHz and a power density of 0.5-3 W / kg to the rice at a ratio of 1:3 between operation and shutdown time, with a tempering time of 8-16 minutes for a single cycle.

[0028] At this stage, due to real-time moisture content It is close to the target moisture content. By using low-temperature hot air to evenly remove bound water and extending the tempering time, the internal moisture of the rice grains has sufficient time to reach equilibrium, completely eliminating internal stress and preventing cracking. This process also avoids excessive drying and heat damage, better preserving the rice's nutrients and flavor.

[0029] By monitoring and providing feedback on real-time moisture content, the drying process can be dynamically adjusted according to changes in the moisture content of the rice, achieving precise drying of the rice, avoiding over-drying or under-drying, and improving the appearance quality and nutrient retention of the rice.

[0030] The stirring mechanism promotes the evaporation of moisture from the rice surface and improves the uniformity of heating and drying.

[0031] Example 1 Weigh 1000 kg of japonica rice with an initial moisture content of approximately 24.5%, set the first threshold to 18%, the second threshold to 14%, and the target moisture content to 13.5%.

[0032] During the rapid pre-drying stage: the hot air mechanism is activated, and the rice is dried for 25 minutes at an outlet air temperature of 65℃ and a wind speed of 2.0m / s, so that the real-time moisture content of the rice is reduced to 18%. During the main drying and tempering stage: the hot air mechanism is activated, drying the rice for 10 minutes at an outlet air temperature of 55℃ and a wind speed of 1.2m / s. Then, the hot air mechanism is turned off and the radio frequency heating mechanism is activated, applying a radio frequency electric field with a working frequency of 40MHz and a power density of 1.5 W / kg to the rice at a 1:3 running-to-stop time ratio, tempering the rice for 10 minutes. This drying and tempering cycle is repeated four times, reducing the real-time moisture content of the japonica rice to 14%.

[0033] During the precision drying and tempering stage: The hot air mechanism is activated, drying the rice for 4 minutes at an outlet air temperature of 45℃ and a wind speed of 0.8m / s. Then, the hot air mechanism is turned off, and the radio frequency heating mechanism is activated, applying a radio frequency electric field with a working frequency of 50MHz and a power density of 1 W / kg to the rice at a 1:3 running-to-stop time ratio, tempering the rice for 12 minutes. This cycle of drying and tempering is repeated three times until the real-time moisture content of the rice drops to 13.5%, at which point drying is stopped.

[0034] Total drying time: 25 + 80 + 48 = 153 minutes.

[0035] Increase in the rate of breakage: After drying, the rate of breakage increased by 2.1% compared with that before drying.

[0036] Moisture content uniformity: The moisture content range of samples taken from different locations in the drying chamber is less than 0.8%.

[0037] Sensory characteristics and quality: The rice grains are golden and bright in color, with no burnt grains, and have a high taste value after steaming or cooking.

[0038] Example 2 Weigh 800 kg of indica rice with an initial moisture content of approximately 20.0%, set the first threshold at 19%, the second threshold at 14%, and the target moisture content at 13%.

[0039] During the rapid pre-drying stage: the hot air mechanism is activated, and the rice is dried for 15 minutes at an outlet air temperature of 60℃ and a wind speed of 2.2m / s, so that the real-time moisture content of the rice is reduced to 19%. During the main drying and tempering stage: the hot air mechanism is activated, drying the rice for 8 minutes at an outlet air temperature of 50℃ and a wind speed of 1.5m / s. Then, the hot air mechanism is turned off and the radio frequency heating mechanism is activated, applying a radio frequency electric field with a working frequency of 35MHz and a power density of 1.8W / kg to the rice at a 1:3 running-to-stop time ratio, tempering the rice for 8 minutes. This drying and tempering cycle is repeated 5 times, reducing the real-time moisture content of the japonica rice to 14%.

[0040] During the precision drying and tempering stage: The hot air mechanism is activated, drying the rice for 3 minutes at an outlet air temperature of 40℃ and a wind speed of 0.6 m / s. Then, the hot air mechanism is turned off, and the radio frequency heating mechanism is activated, applying a radio frequency electric field with a working frequency of 50 MHz and a power density of 1 W / kg to the rice at a 1:3 running-to-stop time ratio, tempering the rice for 10 minutes. This drying and tempering cycle is repeated twice, reducing the real-time moisture content of the rice to 13%, at which point drying is stopped.

[0041] Total drying time: 15 + 80 + 26 = 121 minutes.

[0042] Increase in the rate of breakage: After drying, the rate of breakage increased by 1.8% compared with that before drying.

[0043] Moisture content uniformity: The moisture content range of samples taken from different locations in the drying chamber is less than 0.7%.

[0044] Sensory characteristics and quality: The rice grains are golden and bright in color, with no burnt grains, and have a high taste value after steaming or cooking.

[0045] Comparative Example 1000 kg of japonica rice with an initial moisture content of approximately 24.5% was weighed and dried for 20 minutes at a hot air temperature of 68℃ and an air velocity of 1.5 m / s. Then, it was allowed to rest in a tempering chamber at 45℃ for 60 minutes for tempering. Next, it was dried for 30 minutes at a hot air temperature of 55℃ and an air velocity of 1.5 m / s, and then allowed to rest at 40℃ for 90 minutes. Finally, it was cooled to ambient temperature using a cold air blower.

[0046] Total drying time: 20 + 60 + 30 + 90 = 200 minutes.

[0047] Increase in the rate of breakage: Samples were taken after drying and tested. The rate of breakage increased by 7.5% compared with that before drying.

[0048] Moisture content uniformity: After multi-point sampling and testing, the average moisture content after drying was 12.8%, with some areas having a moisture content <12.0% and others having a moisture content >14.0%, indicating poor uniformity.

[0049] As can be seen from the above embodiments and comparative examples, this application has the following advantages: 1. By combining hot air drying with radio frequency rewarming, the total drying time is significantly shortened; 2. Extremely low breakage rate and excellent moisture content uniformity ensure the quality of the final rice product; 3. Closed-loop control based on real-time moisture content ensures stable and reliable process with good repeatability, making it suitable for modern grain processing centers.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A preparation process for rapid drying of rice, characterized in that, Includes the following steps: Step S1. Place the rice to be dried into the drying chamber and set the first threshold. Second threshold and target moisture content ,in, ; Step S2. Periodically obtain the current moisture content of the rice using a moisture content testing agency. The current moisture content With the first threshold Second threshold and target moisture content contrast: like Then, through the hot air mechanism at the first temperature Rapid pre-drying of rice; like Then, through the hot air mechanism at a second temperature The rice undergoes primary drying and tempering processes; like Then, through the hot air mechanism at a third temperature Rice undergoes precise drying and tempering; in, .

2. The preparation process for rapid drying of rice according to claim 1, characterized in that, The first threshold The second threshold is 18%-20%. It is 14%-16%.

3. The preparation process for rapid drying of rice according to claim 1, characterized in that, During the rapid pre-drying stage, the temperature of the hot air mechanism is 50-70℃, the wind speed is 1.5-2.5m / s, and the time is 10-30min.

4. The preparation process for rapid drying of rice according to claim 1, characterized in that, During the main drying and tempering stage, drying and tempering alternate in a cycle. During drying, the temperature of the hot air mechanism is 40-60℃, the wind speed is 1.0-1.5m / s, and the drying time is 8-12min. During tempering, the hot air mechanism stops working, and the tempering time is 8-12min.

5. The preparation process for rapid drying of rice according to claim 1, characterized in that, During the precise drying and tempering phase, drying and tempering alternate in a cycle. During drying, the temperature of the hot air mechanism is 30-50℃, the wind speed is 0.5-1.0m / s, and the drying time is 3-5min per cycle. During tempering, the hot air mechanism stops working, and the tempering time is 8-16min per cycle.

6. The preparation process for rapid drying of rice according to claim 1, characterized in that, The drying chamber is equipped with a radio frequency heating mechanism. During the tempering process, the radio frequency heating mechanism intermittently applies a radio frequency electric field with a working frequency of 30-50MHz and a power density of 0.5-3 W / kg to the rice.

7. The preparation process for rapid drying of rice according to claim 1, characterized in that, The drying chamber is equipped with a stirring mechanism, and the stirring speed of the stirring mechanism is 2-5 rpm.

8. The preparation process for rapid drying of rice according to claim 1, characterized in that, Step S1 also includes: Step S11. Determine the initial moisture content of the rice to be dried using the oven drying method. ; Step S12. Obtain the second initial moisture content of the rice to be dried using a moisture content testing agency. ; Step S13. Based on the first initial moisture content With the second initial moisture content The difference is used to calibrate the readings of the moisture content testing agency.

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