Continuous circular processing method for rice

Abstract

The invention discloses a continuous circular processing method for rice, and belongs to the technical field of grain processing.The method takes fresh rice as a raw material and sequentially comprises the steps that cleaning pretreatment and dewatering are conducted through a cleaning-dewatering-drying-screening integrated system; shelling after magnetic separation; the hulled materials are divided into A-grade brown rice and B-grade materials through laser thickness grading; performing polishing and color sorting on the A-grade brown rice to obtain a finished product; mixing the B-grade material with the broken rice in the color sorting procedure according to a proportion, and treating the mixture in a low-speed flexible polishing machine integrating online sorting; after discharging of the equipment is graded in real time, complete rice grains are collected into finished products, and to-be-treated semi-finished products flow back to an inlet to be circularly treated until the standard is reached. Through source cleaning treatment and intelligent circulation based on real-time quality feedback, the processing problem of fresh rice is cooperatively solved, the head rice rate and the by-product recycling rate are remarkably increased, and the system has the outstanding advantages of being energy-saving, efficient and stable in product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of grain processing, in particular to a continuous circulation processing method for rice. BACKGROUND

[0002] Grain processing, especially rice processing, is a key industry to ensure the supply of global staple food. The core goal of its technological development has always been around how to continuously improve the head rice rate, effectively reduce the comprehensive energy consumption, and continuously improve the quality and safety of the final product. At present, the rice processing flow widely adopted at home and abroad basically follows the linear process mode of "cleaning → hulling → separation of husked rice → milling → polishing → grading". Although this mode is mature in technology, its inherent limitations have increasingly become a bottleneck restricting the further upgrading and benefit improvement of the industry.

[0003] Specifically, the existing technology at least has the following outstanding problems: The current process generally uses dry cleaning (such as vibrating screen, stone remover) to process dry paddy, which can only remove part of the light impurities and stones, and has limited effect on removing dust, microorganisms and pesticide residues attached to the surface of paddy. This leads to the direct entry of unclean raw materials into subsequent processing, not only intensifying the load of polishing, color selection and other finishing processes, affecting the hygiene indicators (such as total bacterial count) of the final product, but also accelerating the wear and tear of polishing machines, screens and other equipment. In addition, for fresh paddy that has not been dried in time, the existing technology lacks an efficient and continuous pretreatment scheme, and often causes mold due to stacking, resulting in resource waste.

[0004] Although the existing technology has paid attention to the recovery of by-products, the method is relatively extensive. For example, Chinese patent document CN111992482B discloses a device that combines white rice grading and magnetic separation, and mentions re-polishing of broken rice. However, such schemes mostly use simple recovery with fixed paths or fixed proportions, and mix different quality broken rice and unripe grains (B-grade material) without distinction, and then directly return them to the main milling or polishing equipment for high-intensity reprocessing. This "one-size-fits-all" circulation mode lacks real-time sensing and precise control of the material state, which can easily lead to two adverse consequences: first, the B-grade material with intact structure is broken again under strong force; second, the broken rice formed is further ground in the circulation, further reducing its value. This not only makes it difficult to effectively improve the head rice rate, but also may increase energy consumption, making it difficult to break through the head rice rate after reaching a certain level.

[0005] The control systems of existing production lines are mostly isolated or semi-automatic, lacking a unified intelligent management platform. For example, Chinese patent document CN218048036U discloses a cleaning device with a water circulation structure, but it only focuses on improving a single link and fails to achieve efficient integration with processes such as dewatering, screening, and drying. Material transfer carries the risk of stagnation and cross-contamination. The lack of overall control results in high energy consumption, including water and electricity, and the stability of product quality heavily relies on operator experience.

[0006] In summary, there is an urgent need in this field for a rice processing method that can fundamentally achieve source purification, intelligent recycling, and global control, in order to systematically break through the limitations of existing technologies in terms of yield, resource utilization, and product quality. Summary of the Invention

[0007] The purpose of this invention is to overcome the aforementioned technical difficulties and provide a method for continuous recycling of rice that is efficient, energy-saving, high-yield, and produces stable product quality.

[0008] To achieve the above objectives, the technical solution adopted is: a continuous recycling method for rice, comprising the following steps: S1. Pre-treatment: Fresh rice enters the integrated washing-dehydration-drying-screening system through the feeding device, where it undergoes continuous water circulation washing, dehydration, low-temperature drying and screening to control the material moisture content at 12%-14%. S2, Magnetic separation: Magnetic separation of the screened material; S3. Thickness grading: The washed material is dehulled and then classified into Grade A brown rice and Grade B material by thickness grading. S4. Processing Grade A Brown Rice: Grade A brown rice is polished and color sorted in sequence to obtain finished rice and separate broken rice. S5. Processing Grade B material: Grade B material is mixed with broken rice from step S4 at a mass ratio of (2-5):1 and then processed in a low-speed flexible polishing machine with integrated online sorting. S6. Diversion: The integrated online sorting low-speed flexible polishing machine performs real-time classification of its output, dividing it into three streams: The first batch: whole rice grains, meeting the finished product standard, with a whole rice grain content of ≥85%, are incorporated into the B-grade finished product area; The second type: newly harvested broken rice, collected as a byproduct; The third type: semi-finished products to be processed, whose main components are whole rice grains with intact structure but substandard surface smoothness, with the content of whole rice grains <85%; S7. Circulation Processing: The third stream of "semi-finished product to be processed" is returned to the inlet of the integrated online sorting low-speed flexible polishing machine for circulation processing.

[0009] Furthermore, the integrated system for washing, dehydrating, drying, and sieving in step S1 is equipped with a three-stage filtration and water circulation device, wherein the first stage filtration is an 80-100 mesh filter, the second stage filtration is an activated carbon adsorption layer, and the third stage filtration is a ceramic membrane filter assembly, with a water circulation utilization rate of ≥90%.

[0010] Furthermore, the low-temperature drying in step S1 adopts a hot air circulation method, with the hot air temperature controlled at 60-70℃, reducing the material moisture content from 15%-20% to 12%-14%.

[0011] Furthermore, the thickness grading in step S3 uses a laser thickness sensor, and the grading standard is that the thickness of Grade A brown rice is 2.2-2.8 mm, and the thickness of Grade B material is <2.2 mm or >2.8 mm, with a grading accuracy of ≥98.5%.

[0012] Furthermore, in step S5, the mixing mass ratio of grade B material to broken rice is 3:1.

[0013] Furthermore, the polishing pressure of the low-speed flexible polishing machine is controlled at 0.1-0.3MPa, and the spindle speed is 200-400 r / min.

[0014] Furthermore, the real-time grading in step S6 is achieved through an online color sorting device based on image recognition or a combination of airflow and vibrating screen.

[0015] Furthermore, in step S7, the maximum number of times the third material is circulated is set to 2-5 times; if the maximum number of times is exceeded, it is collected as a low-level by-product.

[0016] Furthermore, the entire process of steps S1 to S7 is automatically adjusted by the PLC control unit based on integrated sensor feedback data.

[0017] The beneficial effects of adopting the above scheme are as follows: This continuous rice processing method, through the integrated design of "washing-dehydration-drying-screening", removes dust, mud, microorganisms and residual impurities attached to the surface of rice from the source.

[0018] Using fresh rice directly as the processing raw material is not only the fundamental feature that distinguishes this method from the traditional dry rice processing mode, but also an important prerequisite for achieving a series of subsequent beneficial effects.

[0019] This greatly reduces the load on subsequent polishing, color sorting and other processes, and reduces equipment wear and process fluctuations caused by surface impurities.

[0020] This lays a solid foundation for obtaining high-quality finished rice with higher gloss and lower total bacterial count, realizing an industrial upgrade from "processing" to "clean processing".

[0021] The mixture of Grade B material and broken rice is flexibly processed by an "integrated online sorting low-speed flexible polishing machine", and the output is immediately divided into three streams: finished product, broken rice and semi-finished product to be processed.

[0022] This design ensures that structurally intact grains (semi-finished products awaiting processing) with the potential to become whole rice are continuously processed until they meet the standards, rather than being indiscriminately downgraded along with broken rice. This precise processing mode, tailored to the specific materials, can increase the whole rice yield by another 3-5 percentage points on top of the current highest level, approaching the theoretical limit.

[0023] By actively and meticulously reprocessing Grade B rice and broken rice, low-value byproducts from traditional processes are transformed on a large scale into qualified finished products, achieving a byproduct resource utilization rate of over 90%. This represents a fundamental shift from "waste disposal" to "resource recycling." In summary, this invention, through four key technological pillars—intelligent recycling, integrated design, global automation, and resource recycling—successfully constructs a new, highly efficient, energy-saving, high-yield rice processing model with stable product quality, possessing significant value for industrial promotion.

[0024] The integrated design and three-stage water circulation system in S1 achieve a water recycling rate of over 90%, reducing water consumption per ton-meter by 60%-70% compared to traditional processes. Simultaneously, optimized pretreatment and global PLC intelligent control reduce ineffective energy consumption at each stage, resulting in a comprehensive reduction of over 20% in power consumption.

[0025] The entire process is uniformly controlled by a PLC unit, and key process parameters (such as moisture content, polishing pressure, and sorting threshold) are precisely and automatically controlled, which greatly reduces the reliance on operator experience and ensures the extreme stability of product quality and the efficient and continuous operation of the production line.

[0026] In summary, by overcoming technological biases and introducing source cleaning, combined with intelligent quality feedback loops and global automated control, this invention has successfully constructed a new rice processing model characterized by high quality, high yield, high resource utilization, low energy consumption, and low emissions. This results in a synergistic and amplified comprehensive technological effect, possessing significant industrial promotion value and economic benefits. Attached Figure Description

[0027] Figure 1 This is a flowchart of the continuous recycling method for rice according to the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Example 1 The technical solution of this invention will be described in detail. All embodiments and comparative examples use fresh rice from the same batch with a moisture content of approximately 28% as raw material to control for variables. Using fresh rice as raw material is a crucial prerequisite that distinguishes this method from traditional processing and enables the achievement of subsequent beneficial effects.

[0030] A method for continuous recycling of rice includes the following steps: implementing the full-process scheme as described in claims 1-9.

[0031] Pre-processing: Fresh rice enters the integrated washing-dehydration-drying-screening system at a rate of 5 tons / hour.

[0032] Cleaning and circulation: A three-stage filtration and water circulation system is used (first stage 100 mesh, second stage activated carbon, third stage ceramic membrane), with a water recycling rate of 92%.

[0033] Dehydration and drying: After washing, the material is centrifuged to dehydrate and then enters a 65±5℃ hot air circulating drying unit to stably control the moisture content of the material at 13.5±0.5%.

[0034] Magnetic separation and dehulling: After screening, the material undergoes magnetic separation to remove metal impurities. It then enters a rubber roller dehulling machine for dehulling.

[0035] Grading and Mainstream Processing: After hulling, the material is separated into Grade A brown rice (thickness 2.2-2.8mm) and Grade B material by a laser thickness grading machine (accuracy 98.8%). Grade A brown rice is polished and color sorted to obtain the finished product.

[0036] Mixing: Grade B material is mixed with broken rice produced in the color sorting process at a mass ratio of 3:1.

[0037] Processing and Sorting: The mixture enters a low-speed flexible polishing machine with integrated online sorting (polishing pressure 0.2 MPa, spindle speed 300 r / min). The output is separated into three streams in real time by an image recognition-based online color sorting device: First strand (whole rice grains, ≥85%): Added to the finished product.

[0038] The second stream (newly broken rice): collection.

[0039] The third stock (semi-finished product to be processed, <85%): proceeds to the next stage.

[0040] Reflux detection: The third stream of material is recirculated a maximum of 3 times. If the maximum number of times is not exceeded, the material is recirculated back to the inlet of the low-speed flexible polishing machine; if the maximum number of times is exceeded, the material is collected as a low-level by-product.

[0041] Control: The entire process is automatically regulated by the PLC control unit.

[0042] The system ran continuously and stably for 4 hours, recording various data during that time.

[0043] Comparative Example 1 Based on Example 1, steps S6 and S7 in claim 1 are omitted. That is, after mixing grade B material and broken rice at a ratio of 3:1, the mixture is processed once in the same low-speed flexible polishing machine. Regardless of the quality of the output, it is directly collected (whole rice grains are used as finished products, and the rest are used as by-products), without forming a closed-loop reflux based on quality feedback. All other parameters are exactly the same as in Example 1.

[0044] Comparative Example 2 Based on Example 1, step S5 in claim 1 is omitted. That is, the grade B material after thickness grading is not mixed with the broken rice generated in each process of the system, and is instead collected directly as waste or low-grade by-products. Only grade A brown rice is processed into finished products through subsequent polishing and color sorting. All other parameters are exactly the same as in Example 1.

[0045] Comparative Example 3 This comparative simulation is the closest existing technology, which adopts the traditional linear process of "cleaning-hulling-milling rice" and omits step S1 in claim 1 of this invention.

[0046] Pre-treatment: The rice is not washed, dehydrated and dried. It is directly cleaned by a conventional vibrating screen and destoner.

[0047] Subsequent steps: The cleaned paddy rice undergoes magnetic separation, hulling, and thickness grading. Grade A brown rice is polished and color sorted. Grade B material and broken rice are not mixed with or further processed (i.e., S5-S7 are simultaneously omitted) and are collected directly as by-products.

[0048] Example 2 The table below compares the key technical indicators of Example 1 with those of the three comparative examples within the same operating time. Evaluation index Example 1 (full scheme of the invention) Comparative Example 1 (no intelligent reflux) Comparative Example 2 (no mixed reprocessing) Comparative Example 3 (prior art: no cleaning-drying) Whole rice rate (%) 70.5 66.8 63.2 61.5 By-product resource utilization rate (%) 91.5 75.3 0 0 Water consumption per ton of rice (tons) 0.38 0.39 0.40 0.10 (only equipment cooling) Total number of microbial colonies in finished product (CFU / g) <500 <500 <500 >5000 Polisher screen replacement cycle (hours) >200 >200 >200 ~ 80 Surface finish of finished rice (sensory score / 10) 9.0 9.0 8.5 7.5 Dust concentration in production environment (mg / m³) <1.0 <1.0 <1.0 >5.0

[0049] 1. As the data shows, the total number of microbial colonies and surface smoothness of the finished product in Example 1 are significantly better than those in Comparative Example 3. This directly proves that step S1, through source purification, fundamentally improves the hygiene and safety of the product and its commercial value, which is impossible to achieve with traditional dry processing.

[0050] The screen replacement cycle of the polishing machine in Example 1 is much longer than that in Comparative Example 3, which proves that step S1 removes abrasive impurities (such as mud and sand) from the surface of the rice, significantly reduces the wear of subsequent finishing equipment, reduces downtime, and improves production efficiency.

[0051] The dust concentration in the production environment of Example 1 is significantly lower, creating a more friendly and environmentally friendly production environment.

[0052] Although Comparative Example 3 has a slight advantage in water consumption, the present invention controls the absolute water consumption to an extremely low level (0.38 tons / ton-meter) through the water circulation system (weights 2 and 3) in S1. The present invention achieves a comprehensive and leapfrog improvement in product quality, equipment lifespan, and production environment with acceptable and optimized water consumption. This is precisely the unexpected technical effect brought about by overcoming the technical prejudice that "rice initial processing does not require washing."

[0053] 2. The head rice yield of Example 1 (70.5%) was significantly higher than that of Comparative Example 1 (66.8%) and Comparative Example 3 (61.5%). This comprehensively demonstrates the synergistic contribution of the entire system to improving the rice yield, from source loss reduction in S1 to end-of-pipe recovery in S5-S7.

[0054] The by-product resource utilization rate of Example 1 (91.5%) is incomparable to that of Examples 2 and 3 (both 0%), highlighting the revolutionary nature of this invention in resource recycling.

[0055] Example 3 Based on Example 1, the applicant conducted a comparative experiment on the mixing process: Grade B material was mixed with broken rice produced in the color sorting process at a mass ratio of 3:1.

[0056] The processing was completed with B-grade feed and broken rice in ratios of 3:1, 2:1, and 5:1, and without adding broken rice, while keeping other parameters unchanged. The following experimental data were collected. Evaluation index Proportion 5:1 Proportion 3:1 Proportion 2:1 Proportion 0 Whole rice rate (%) 69.2 70.5 68.0 63.2 By-product resource utilization rate (%) 88.1 91.5 89.5 0 Secondary polishing discharge compliance rate (single time) 85% 88% 82% Not applicable Circulation system load Lower Moderate Higher None Broken rice content in final product (%) 2.0 2.1 2.8 3.5

[0057] Comparing the ratio of 3:1 to 0, there is a significant improvement in the head rice yield and by-product resource utilization rate. This proves that mixing broken rice with Grade B material and then performing secondary polishing can effectively "attach" or "integrate" some of the broken rice onto the Grade B material, or improve its appearance through flexible polishing, thereby transforming the originally worthless broken rice into a valuable product. This is the key to improving the resource utilization rate.

[0058] A low ratio (e.g., 5:1) results in too much Grade B material and too little broken rice. The system's capacity to process broken rice is not fully utilized, leading to a lower by-product resource utilization rate. Additionally, the material's flowability within the polishing machine is slightly poor, affecting the single-pass processing effect (slightly lower output compliance rate).

[0059] Excessive ratio (e.g., 2:1): The proportion of broken rice is too high. Too much broken rice is difficult to effectively "rescue" during the cycle and tends to accumulate in the polishing machine, affecting the contact between the effective working parts and whole rice grains, leading to a decrease in the whole rice yield and the output compliance rate. At the same time, over-processing increases the broken rice content in the finished product. The system load also increases due to the increase in ineffective cycles.

[0060] A suitable ratio (3:1) achieves peak performance in head rice yield, by-product resource utilization rate, and output compliance rate. At this ratio, grade B material and broken rice achieve the best balance in terms of volume and characteristics, which can fully utilize broken rice while ensuring that grade B material acts as the "skeleton" to support the effective polishing process, allowing the intelligent circulation system to operate in the most efficient range.

[0061] Conclusion: Experimental data proves that mixing grade B material with broken rice in step S5 is necessary, and (2-5):1 is a range that can produce excellent technical effects. Among them, 3:1 is the optimal implementation ratio, which was obtained through a large number of experiments and provides a key guarantee for the efficient operation of the entire intelligent circulation system, reflecting the creativity of the invention.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A continuous cycle processing method of rice, characterized by: Comprise the following steps: S1, pretreatment: fresh rice through the feeding device into the cleaning-dewatering-drying-screening integrated system, continuous water circulation cleaning, dewatering, low temperature drying and screening, the moisture content of the material is controlled at 12%-14%; S2, magnetic separation: the screened material is subjected to magnetic separation; S3, thickness classification: the cleaned material is shelled, and the shelled material is classified into A-grade brown rice and B-grade material by thickness classification; S4, processing A-grade brown rice: A-grade brown rice is sequentially polished and color-selected to obtain finished rice and separate out broken rice; S5, processing B-grade material: B-grade material and broken rice from step S4 are mixed at a mass ratio of (2-5):1, and then enter the integrated online sorting low-speed flexible polisher for processing; S6, diversion: the integrated online sorting low-speed flexible polisher classifies the discharge thereof in real time to divide it into three streams: The first stream: complete rice grains meeting the finished product standard, the content of complete rice grains ≥85%, which is collected into the B-grade finished product area; The second stream: new broken rice, which is collected as byproduct; The third stream: to-be-processed semi-finished product, which mainly comprises whole rice grains with complete structure but substandard surface smoothness, the content of complete rice grains <85%; S7, circulating processing: the third stream of "to-be-processed semi-finished product" is returned to the inlet of the integrated online sorting low-speed flexible polisher for circulating processing.

2. The continuous circulating processing method of rice according to claim 1, characterized by: The cleaning-dewatering-drying-screening integrated system in step S1 is provided with a three-stage filtering water circulation device, wherein the first-stage filtering is a 80-100 mesh filter screen, the second-stage filtering is an activated carbon adsorption layer, and the third-stage filtering is a ceramic membrane filtering assembly, and the water circulation utilization rate is ≥90%.

3. The continuous circulating processing method of rice according to claim 1, characterized by: The low-temperature drying in step S1 adopts a hot air circulation mode, the hot air temperature is controlled at 60-70℃, and the moisture content of the material is reduced from 15%-20% to 12%-14%.

4. The continuous circulating processing method of rice according to claim 1, characterized by: The thickness classification in step S3 adopts a laser thickness measuring sensor, and the classification standard is that the thickness of A-grade brown rice is 2.2-2.8mm, the thickness of B-grade material is <2.2mm or >2.8mm, and the classification accuracy is ≥98.5%.

5. The continuous circulating processing method of rice according to claim 1, characterized by: In step S5, the mixed mass ratio of B-grade material and broken rice is 3:

1.

6. The continuous circulating processing method of rice according to claim 1, characterized by: The polishing pressure of the low-speed flexible polisher is controlled at 0.1-0.3MPa, and the main shaft speed is 200-400 r / min.

7. The continuous circulating processing method of rice according to claim 1, characterized by: The real-time classification in step S6 is realized by an online color selection device based on image recognition or a combined device of air flow and vibration screen.

8. The continuous circulating processing method of rice according to claim 1, characterized by: In step S7, the circulation number of the third stream of material is set to an upper limit of 2-5 times; after exceeding the upper limit, it is collected as low-grade byproduct.

9. The continuous circulating processing method of rice according to claim 1, characterized by: The whole process of steps S1 to S7 is automatically adjusted by a PLC control unit according to the integrated sensor feedback data.

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