Green and environment-friendly processing method of low-emission rice

Abstract

The invention discloses a green and environment-friendly processing method of low-emission rice, relates to the technical field of rice processing, and solves the problems of large emission of dust and wastewater, high energy consumption and low resource utilization rate in traditional processing. The method comprises the steps of raw grain pretreatment and purification, graded low-temperature grinding, biodegradable additive polishing, by-product resource recycling, tail gas multi-stage purification, wastewater treatment circulation and process regulation and control in combination with a multi-parameter optimization model. Results show that dust emission, wastewater reuse rate and unit energy consumption are reduced, byproduct utilization rate is increased, no chemical additive is left, rice safety is guaranteed, and the method is suitable for large-scale green processing.

Description

Technical Field

[0001] This invention relates to the field of rice processing technology, specifically to a green and environmentally friendly processing method for low-emission rice. Background Technology

[0002] Rice, as a major grain crop in my country, has a large-scale processing industry. However, traditional rice processing methods present numerous environmental and resource problems. Traditional processing techniques often involve simple milling, chemical polishing, extensive wastewater discharge, and the disposal of byproducts, resulting in high dust emission concentrations during processing. The wastewater is far above environmental standards; direct discharge of wastewater causes waste of water resources, with COD concentrations typically ranging from 200 to 500 mg / L, polluting the aquatic environment; the processing energy consumption is high, with energy consumption per unit product being approximately 80-100 kWh / t, and the utilization rate of by-products such as rice bran and broken rice is less than 30%, resulting in serious resource waste.

[0003] In existing technologies, some rice processing methods attempt to reduce pollution by improving milling equipment or simply treating wastewater, but these methods have significant drawbacks: First, the milling process lacks temperature control, leading to nutrient loss in the rice and generating large amounts of dust. Second, the chemical additives used in the polishing process are difficult to degrade, leaving residues on the rice surface and affecting food safety. Third, the exhaust gas and wastewater treatment processes are simplistic, with limited purification effects, failing to meet emission standards. Fourth, a comprehensive energy consumption and emission optimization mechanism has not been established, making it difficult to balance environmental protection and economic efficiency. Therefore, developing a green rice processing method that combines low emissions, low energy consumption, high resource utilization, and food safety assurance has become a pressing technical challenge for the industry. Summary of the Invention

[0004] This application provides a green and environmentally friendly processing method for low-emission rice, which can achieve low emissions, low energy consumption and efficient resource utilization in the rice processing process, and solve the environmental protection and resource waste problems of traditional processing technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] Firstly, this application provides a green and environmentally friendly processing method for low-emission rice, comprising the following steps:

[0007] The raw grains are pre-treated and purified to remove impurities and harmful substances;

[0008] The pretreated raw grains are milled using a graded low-temperature milling process to obtain coarsely processed rice;

[0009] Using biodegradable and environmentally friendly additives to polish coarsely processed rice yields finely processed rice;

[0010] Byproducts generated during grinding and polishing are recycled and utilized; exhaust gases generated during processing are treated through multi-stage synergistic purification to ensure that exhaust emissions meet environmental protection standards.

[0011] Wastewater generated during processing is treated in stages and then recycled to achieve closed-loop utilization of water resources.

[0012] As a further improvement to the technical solution of the present invention, the pretreatment purification specifically includes: sequentially performing airflow screening, vibration grading for impurity removal, magnetic separation for iron removal, and ultraviolet sterilization, wherein the airflow screening wind speed is 8-12m / s, the vibration grading amplitude is 5-8mm and the frequency is 50-70Hz, and the ultraviolet sterilization wavelength is 253.7nm and the irradiation time is 30-60s.

[0013] As a further improvement to the technical solution of the present invention, the graded low-temperature grinding process specifically includes: using 3-5 stage grinding equipment, with the grinding gaps between each stage being 0.8-1.2mm, 0.5-0.8mm, 0.3-0.5mm, and 0.1-0.3mm respectively (if it is 5 stages, the gaps are increased by 0.05-0.1mm), and the grinding chamber temperature is controlled by a cooling system during the grinding process. The rotational speed gradient for each grinding stage is: Speed ​​difference between adjacent stages .

[0014] As a further improvement to the technical solution of the present invention, the biodegradable and environmentally friendly additive is composed of the following components in parts by weight: 20-30 parts of starch-based polymer, 5-10 parts of plant extract, 10-15 parts of polylactic acid, and 50-60 parts of deionized water. The plant extract is a compound of tea polyphenols and grape seed extract, with a weight ratio of 1:2-3.

[0015] As a further improvement to the technical solution of this invention, the resource recycling of the by-products specifically includes: preparing bio-feed or biodiesel from rice bran through crushing, enzymatic hydrolysis, and fermentation; and preparing rice flour from broken rice through gelatinization and spray drying. The enzymatic hydrolysis process uses a compound enzyme consisting of cellulase, hemicellulase, and amylase, and the hydrolysis temperature is [temperature missing]. The pH value is 4.5-5.5, and the enzymatic hydrolysis time is 2-4 hours.

[0016] As a further improvement to the technical solution of this invention, the multi-stage synergistic purification treatment of the exhaust gas specifically includes: sequentially passing through electrostatic dust removal, activated carbon adsorption, and photocatalytic oxidation. The voltage of the electrostatic dust removal is 30-50kV, and the space velocity of the activated carbon adsorption layer is... Photocatalytic oxidation uses Composite catalyst, UV irradiation intensity is Dust concentration in the exhaust gas after treatment VOCs concentration ≤ .

[0017] As a further improvement to the technical solution of this invention, the wastewater staged treatment specifically includes: sequentially passing through a screen filter, anaerobic digestion, aerobic biochemical treatment, membrane separation, and disinfection. The temperature of the anaerobic digestion is... The hydraulic retention time is 12-24 hours, and the aerobic biological treatment adopts the MBR process with a membrane flux of [missing information]. Disinfection is carried out using ultraviolet light, and the treated wastewater... , It is used repeatedly for cleaning raw grains and cooling equipment.

[0018] As a further improvement to the technical solution of this invention, it also includes real-time monitoring of energy consumption and emissions during the processing. This involves collecting energy consumption data, exhaust gas emission concentrations, and wastewater quality parameters at each stage of the process using sensors, and dynamically adjusting process parameters based on a multivariate optimization model. The multivariate optimization model is as follows: ,

[0019] Where E represents the optimized energy consumption per unit of product. This is the initial energy consumption baseline value. Weighting coefficients ( =0.3-0.5, =0.2-0.3, =0.1-0.2), To improve grinding efficiency, The reference grinding efficiency is T, and the actual grinding temperature is T. For the optimal grinding temperature ( P represents the actual grinding pressure. The reference grinding pressure.

[0020] As a further improvement to the technical solution of the present invention, the polishing process parameters are as follows: polishing machine speed is 800-1200 r / min, polishing time is 30-60 s, and the amount of environmentally friendly additive sprayed is [amount missing] times the weight of rice. During the polishing process, the ambient humidity is controlled to be .

[0021] As a further improvement to the technical solution of this invention, the raw grain is rice, and the pretreatment process includes a screening and destoning step, using a gravity destoner with an air volume of [missing information]. The inclination angle of the sieve surface is Stone removal efficiency ≥99%.

[0022] Secondly, this application also provides a system for realizing the above-mentioned low-emission green and environmentally friendly rice processing method, including a raw grain pretreatment unit, a graded low-temperature milling unit, an environmentally friendly polishing unit, a by-product recycling unit, a tail gas purification unit, a wastewater treatment unit, and a monitoring and control unit. Each unit is connected in sequence through conveying equipment and pipelines to realize the automation and continuity of the entire processing process.

[0023] The green and environmentally friendly processing method for low-emission rice proposed in this application has the following advantages compared to existing technologies:

[0024] This invention achieves efficient removal of impurities and harmful substances from raw grains through pretreatment purification, providing a clean raw material foundation for subsequent processing. The graded low-temperature milling process reduces dust generation and nutrient loss during milling, while also lowering the broken rice rate and ensuring processing quality. The application of biodegradable and environmentally friendly polishing additives avoids the risk of residue from traditional chemical additives, improving the safety and gloss of rice. By-product recycling transforms waste such as rice bran and broken rice into high-value-added products, significantly improving resource utilization and reducing waste. Multi-stage synergistic purification of exhaust gas effectively reduces dust and VOC emission concentrations, meeting environmental standards. Graded wastewater treatment followed by recycling achieves closed-loop water resource utilization, significantly reducing wastewater discharge and water consumption. These six core steps work synergistically, covering the entire process from raw material processing to end-of-pipe emissions, meeting green processing requirements. This not only significantly reduces pollutant emissions and energy consumption during rice processing but also ensures rice quality and safety, improves resource utilization efficiency and economic benefits. It is suitable for large-scale rice processing production, providing key technological support for the green transformation of the rice processing industry towards low emissions, high environmental protection, and high resource utilization. Attached Figure Description

[0025] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the process flow for a low-emission, green, and environmentally friendly rice processing method in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will be described in detail below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0028] Reference Figure 1 Firstly, this application provides a green and environmentally friendly processing method for low-emission rice, comprising the following steps:

[0029] The raw grains are pre-treated and purified to remove impurities and harmful substances;

[0030] The pretreated raw grains are milled using a graded low-temperature milling process to obtain coarsely processed rice;

[0031] Using biodegradable and environmentally friendly additives to polish coarsely processed rice yields finely processed rice;

[0032] Byproducts generated during grinding and polishing are recycled and utilized; exhaust gases generated during processing are treated through multi-stage synergistic purification to ensure that exhaust emissions meet environmental protection standards.

[0033] Wastewater generated during processing is treated in stages and then recycled to achieve closed-loop utilization of water resources.

[0034] It should be noted that the green and environmentally friendly processing method for low-emission rice achieves green processing throughout the entire process through six core steps: First, the raw grain is pre-treated and purified to remove impurities and harmful substances, providing clean raw materials for subsequent processing; then, a graded low-temperature milling process is used to mill the pre-treated raw grain, reducing dust generation and nutrient loss during processing through gradient milling control and low-temperature environment maintenance, resulting in coarsely processed rice; subsequently, biodegradable environmentally friendly additives are used to polish the coarsely processed rice, improving the rice's gloss while avoiding chemical residues; by-products such as rice bran and broken rice generated during milling and polishing are transformed into high-value-added products through resource utilization processes; the exhaust gas generated during processing is treated using a multi-stage synergistic purification process to sequentially remove dust and volatile organic compounds; and the processing wastewater is treated in stages and then recycled for raw grain washing and equipment cooling, achieving closed-loop utilization of water resources.

[0035] The method of this invention covers the entire process of green processing from raw material handling to end-of-pipe emissions. It ensures the cleanliness of raw materials through pretreatment and purification, reduces dust and nutrient loss through graded low-temperature milling, ensures food safety through biodegradable additives, improves resource utilization through by-product recycling, and achieves low emissions and water conservation through exhaust gas purification and wastewater recycling. The overall process significantly reduces pollutant emissions and energy consumption in rice processing, while ensuring rice quality and safety and increasing economic benefits. It provides key technical support for the green transformation of the rice processing industry and is suitable for large-scale production.

[0036] In some embodiments, the pretreatment purification specifically includes: sequentially performing airflow screening, vibration grading for impurity removal, magnetic separation for iron removal, and ultraviolet sterilization, wherein the airflow screening wind speed is 8-12m / s, the vibration grading amplitude is 5-8mm and the frequency is 50-70Hz, and the ultraviolet sterilization wavelength is 253.7nm and the irradiation time is 30-60s.

[0037] It should be noted that the pretreatment purification achieves deep purification of the raw grain through a multi-step collaborative process: First, airflow screening is used, with the wind speed controlled at 8-12 m / s, utilizing the buoyancy difference of the airflow to separate light impurities such as rice husks and broken leaves from the raw grain; then, vibration grading is used to remove impurities, with an amplitude of 5-8 mm and a frequency of 50-70 Hz, relying on the grading force generated by vibration to remove medium-sized impurities; subsequently, magnetic separation is used to remove iron and metallic impurities; finally, the raw grain is irradiated with ultraviolet light at a wavelength of 253.7 nm for 30-60 seconds, utilizing the bactericidal effect of ultraviolet light to kill microorganisms on the surface of the raw grain. Precise matching of parameters in each step results in a progressive impurity removal and sterilization effect. This pretreatment purification process, through multi-step parameter optimization, achieves efficient separation of light impurities, medium-sized impurities, and metallic impurities, with a high impurity removal rate. Simultaneously, ultraviolet sterilization with a specific wavelength and duration ensures that the microbial indicators of the raw grain meet standards, avoiding damage to equipment from impurities and the impact of microorganisms on rice quality during subsequent processing. This provides high-purity raw materials for subsequent grading, milling, and polishing, ensuring the safety and processing stability of the final rice product.

[0038] In some embodiments, the graded low-temperature grinding process specifically includes: using a 3-5 stage grinding device, with the grinding gaps for each stage being 0.8-1.2mm, 0.5-0.8mm, 0.3-0.5mm, and 0.1-0.3mm respectively (if there are 5 stages, the gaps are increased by 0.05-0.1mm), and the grinding chamber temperature is controlled by a refrigeration system during the grinding process. The rotational speed gradient for each grinding stage is: Speed ​​difference between adjacent stages .

[0039] It should be noted that the graded low-temperature milling process uses 3-5 stages of tandem milling equipment, with gradient milling gaps set according to the processing precision requirements: the first stage coarse milling gap is 0.8-1.2mm to remove the outer rice husk, the second stage medium milling gap is 0.5-0.8mm to remove some of the rice bran, and the third stage and above fine milling gaps gradually decrease to 0.05-0.3mm to achieve high-precision processing; during the milling process, the temperature of the milling chamber is controlled at a certain level through a cooling system. To avoid starch gelatinization caused by high temperatures; at the same time, set The speed gradient, and the speed difference between adjacent stages This process reduces the impact of crushing forces on rice during milling. The gradient milling gap and speed design effectively reduces the broken rice rate, ensuring rice processing precision. Low-temperature environmental control prevents nutrient loss and quality deterioration. Multi-stage milling reduces the intensity of each milling cycle, lowers dust generation, and improves milling efficiency. The overall process balances processing quality, dust control, and nutrient retention, solving the problems of high broken rice rate, excessive dust, and nutrient loss associated with traditional single-stage milling processes.

[0040] In some embodiments, the biodegradable environmentally friendly additive is composed of the following components in parts by weight: 20-30 parts starch-based polymer, 5-10 parts plant extract, 10-15 parts polylactic acid, and 50-60 parts deionized water, wherein the plant extract is a compound of tea polyphenols and grape seed extract, with a weight ratio of 1:2-3.

[0041] It should be noted that the biodegradable and environmentally friendly additive is formulated with starch-based polymers, plant extracts, polylactic acid, and deionized water in specific weight proportions: 20-30 parts of starch-based polymer provide basic adhesion and gloss enhancement; 5-10 parts of tea polyphenols and grape seed extract (weight ratio 1:2-3) exert antibacterial and antioxidant effects; 10-15 parts of polylactic acid enhance the additive's biodegradability; and 50-60 parts of deionized water serve as a dispersion medium to ensure uniform mixing of all components. During polishing, this additive adheres to the rice surface via spraying, forming a biodegradable protective film, replacing traditional non-biodegradable chemical polishing agents. All components of this environmentally friendly additive are biodegradable, posing no risk of chemical residue and ensuring the safety of rice consumption. The addition of tea polyphenols and grape seed extract enhances the rice's antioxidant and antibacterial capabilities during storage, extending its shelf life. The synergistic effect of the starch-based polymer and polylactic acid ensures that the rice surface achieves the required gloss level. Simultaneously, the additive is easily degradable, avoiding environmental pollution and solving the problems of residue and environmental hazards associated with traditional chemical polishing agents.

[0042] In some embodiments, the recycling of by-products specifically includes: preparing bio-feed or biodiesel from rice bran through crushing, enzymatic hydrolysis, and fermentation; and preparing rice flour from broken rice through gelatinization and spray drying. The enzymatic hydrolysis process uses a compound enzyme consisting of cellulase, hemicellulase, and amylase, and the hydrolysis temperature is [temperature missing]. The pH value is 4.5-5.5, and the enzymatic hydrolysis time is 2-4 hours.

[0043] It should be noted that the resource recycling of by-products employs differentiated processing techniques for different by-products: for rice bran, it is first pulverized, then a compound enzyme mixture of cellulase, hemicellulase, and amylase is added... Enzymatic hydrolysis is performed at pH 4.5-5.5 for 2-4 hours. The hydrolysate is then fermented to prepare bio-feed or used to produce biodiesel via transesterification. For broken rice, 3-5 times its weight of deionized water is added... After gelatinization for 30-40 minutes and cooling, rice flour is prepared by spray drying, achieving high-value conversion of by-products. This process transforms traditionally discarded rice bran and broken rice into high-value-added products such as bio-feed, biodiesel, or rice flour, achieving a resource utilization rate of ≥90% and reducing waste emissions. Differentiated processing techniques are matched to the component characteristics of different by-products to ensure conversion efficiency and product quality, while also increasing additional economic benefits for processing enterprises, realizing "turning waste into treasure," and improving the overall economic benefits and resource utilization efficiency of the industry.

[0044] In some embodiments, the multi-stage synergistic purification treatment of the exhaust gas specifically includes: sequentially passing through electrostatic dust removal, activated carbon adsorption, and photocatalytic oxidation. The voltage of the electrostatic dust removal is 30-50kV, and the space velocity of the activated carbon adsorption layer is... Photocatalytic oxidation uses Composite catalyst, UV irradiation intensity is Dust concentration in the exhaust gas after treatment VOCs concentration ≤ .

[0045] It should be noted that the multi-stage synergistic purification of exhaust gas achieves emission standards through a three-step progressive treatment: the first step uses electrostatic dust removal, applying a voltage of 30-50kV to charge the dust particles in the exhaust gas, which are then captured under the action of the electric field; the second step uses an activated carbon adsorption tower, controlling the space velocity of the adsorption layer to... The third step utilizes the porous structure of activated carbon to adsorb volatile organic compounds in the exhaust gas; Composite catalysts, in Under ultraviolet light irradiation, residual volatile organic compounds are decomposed into carbon dioxide and water, forming a synergistic purification system of "dust removal-adsorption-oxidation". This multi-stage synergistic purification process achieves highly efficient removal of dust and volatile organic compounds, significantly reducing the dust concentration in the treated exhaust gas. volatile organic compound concentration It meets the national comprehensive emission standards for air pollutants; the processes in each step are complementary, avoiding the problem that the effect of a single purification method is limited, reducing the pollution of the atmospheric environment during the processing, and meeting the requirements of green and environmentally friendly production.

[0046] In some embodiments, the wastewater staged treatment specifically includes: sequentially passing through a screen filter, anaerobic digestion, aerobic biochemical treatment, membrane separation, and disinfection. The temperature of the anaerobic digestion is [temperature missing]. The hydraulic retention time is 12-24 hours, and the aerobic biological treatment adopts the MBR process with a membrane flux of [missing information]. Disinfection is carried out using ultraviolet light, and the treated wastewater... , It is used repeatedly for cleaning raw grains and cooling equipment.

[0047] In practice, wastewater staged treatment achieves recycling through a combination of multiple processes: the first step involves filtration through a screen to remove large suspended solids; the second step involves the wastewater entering an anaerobic reactor... The first step involves anaerobic microorganisms decomposing organic matter in wastewater under a hydraulic retention time of 12-24 hours. The second step employs a membrane bioreactor process to control the membrane flux. The first step involves the synergistic removal of residual organic matter through aerobic microorganisms and membrane separation; the fourth step involves ultrafiltration membrane separation and ultraviolet disinfection, ultimately reducing the chemical oxygen demand (COD) of the treated wastewater. Suspended matter The wastewater is recycled for grain washing and equipment cooling. The graded treatment process achieves deep purification of wastewater, and the treated water quality meets the requirements for recycling and reuse, with a wastewater reuse rate of ≥90%. This significantly reduces the consumption of fresh water resources and wastewater discharge, avoiding pollution of the aquatic environment. The biogas produced during the anaerobic treatment process can also be recovered and reused as energy, further improving resource utilization and forming a green production model for water resource recycling.

[0048] In some embodiments, the process also includes real-time monitoring of energy consumption and emissions during processing. Energy consumption data, exhaust gas emission concentrations, and wastewater quality parameters at each stage of the process are collected via sensors. Process parameters are dynamically adjusted based on a multivariate optimization model, wherein the multivariate optimization model is:

[0049] ,

[0050] Where E represents the optimized energy consumption per unit of product. This is the initial energy consumption baseline value. Weighting coefficients ( =0.3-0.5, =0.2-0.3, =0.1-0.2), To improve grinding efficiency, The reference milling efficiency is T, and the actual milling temperature is T. For the optimal grinding temperature ( P represents the actual grinding pressure. The reference grinding pressure.

[0051] It should be noted that real-time monitoring of energy consumption and emissions during the processing involves collecting energy consumption data, exhaust gas emission concentrations, and wastewater quality parameters at each stage of the process using sensors. Process parameters are dynamically adjusted based on a multivariate optimization model, the formula of which is: Where E is the optimized energy consumption per unit product. This is the initial energy consumption baseline value. Weighting coefficients ( , , ), To improve grinding efficiency, The reference grinding efficiency is T, and the actual grinding temperature is T. For the optimal grinding temperature ( P represents the actual grinding pressure. The model uses the benchmark grinding pressure to calculate the optimal combination of process parameters, achieving a dynamic balance between energy consumption and emissions. Real-time monitoring ensures precise control over the processing. The multivariate optimization model dynamically adjusts the process based on actual parameters, avoiding energy waste and excessive emissions caused by fixed parameters. This reduces energy consumption per unit product by more than 30%, while ensuring that emissions always meet environmental standards. The model's weight coefficients are designed to adapt to the influence of different process stages, resulting in more accurate optimization and a synergistic improvement in both environmental protection and economic efficiency.

[0052] In some embodiments, the polishing process parameters are: polishing machine speed of 800-1200 r / min, polishing time of 30-60 s, and the amount of environmentally friendly additive applied is equal to the weight of rice. During the polishing process, the ambient humidity is controlled to be .

[0053] It should be noted that the polishing process achieves a balance between the rice's gloss and safety through precise parameter control: the polishing machine speed is set to... Ensure the rice surface is in full contact with the additives while avoiding excessive friction that could cause breakage; control the polishing time to 30-60 seconds to ensure even adhesion of the additives and the formation of a protective film; set the application rate of the environmentally friendly additives to a percentage of the rice weight. To avoid excessive or insufficient additives leading to poor gloss; at the same time, control the humidity of the polishing environment. To prevent the rice from absorbing or losing moisture during polishing, thus affecting its quality, precise control of polishing parameters ensures the rice surface maintains its gloss. To meet market quality demands; optimization of additive application rate and polishing time reduces additive residue, minimizing residue levels. This ensures food safety; environmental humidity control prevents rice quality deterioration; the overall process improves polishing effect and product stability, solving the problems of uneven gloss and excessive residue caused by the coarse parameters of traditional polishing processes.

[0054] In some embodiments, the raw grain is rice, and the pretreatment process includes a screening and destoning step using a gravity destoner with an air volume of [missing information]. The inclination angle of the sieve surface is Stone removal efficiency ≥99%.

[0055] It should be noted that the screening and destoning step before raw grain pretreatment uses a gravity destoner, which separates the raw grain from the stones by utilizing their specific gravity difference. The air volume of the destoner is set to... The raw grain is suspended by airflow, while stones, due to their higher density, settle; simultaneously, the screen surface inclination angle is set at... Under the combined action of gravity and airflow, stones slide down the screen surface to the stone discharge port, while the raw grain is conveyed forward with the airflow, achieving efficient separation of stones and raw grain with a stone removal efficiency of ≥99%. This screening and stone removal process achieves efficient stone removal through the synergistic effect of specific gravity difference, airflow, and inclination angle, preventing stones from entering subsequent grinding equipment and causing equipment wear or affecting rice quality. The high stone removal efficiency ensures the cleanliness of the raw grain, laying the foundation for subsequent pretreatment steps, reducing impurities in subsequent processing stages, and improving overall processing efficiency and product quality stability.

[0056] Secondly, this application also provides a system for realizing the above-mentioned low-emission green and environmentally friendly rice processing method, including a raw grain pretreatment unit, a graded low-temperature milling unit, an environmentally friendly polishing unit, a by-product recycling unit, a tail gas purification unit, a wastewater treatment unit, and a monitoring and control unit. Each unit is connected in sequence through conveying equipment and pipelines to realize the automation and continuity of the entire processing process.

[0057] To provide a clearer understanding of the invention, the invention is further described below:

[0058] This application provides a green and environmentally friendly processing method for low-emission rice, comprising the following steps:

[0059] Raw grain pretreatment and purification: The raw rice is subjected to a series of processes including sieving to remove stones, airflow screening, vibration grading to remove impurities, magnetic separation to remove iron, and ultraviolet sterilization to remove stones, soil, metal impurities, and microorganisms, resulting in purified raw grain.

[0060] Graded low-temperature milling: The purified raw grain is fed into a multi-stage milling equipment. Through gradient gap control and low-temperature control technology, it undergoes coarse milling, medium milling and fine milling (multi-stage) treatment in sequence to remove rice husks and bran, and obtain coarsely processed rice. The amount of dust generated during the milling process is controlled.

[0061] Environmentally friendly polishing treatment: Biodegradable and environmentally friendly additives are used to polish the coarsely processed rice, removing residual rice bran and enhancing the gloss of the rice, while avoiding chemical residues.

[0062] By-product recycling: By-products such as rice bran and broken rice generated during milling and polishing are processed through enzymatic hydrolysis, fermentation, and drying to produce high-value-added products such as bio-feed, biodiesel, or rice flour.

[0063] Multi-stage synergistic purification of exhaust gas: The dust-laden exhaust gas generated during the processing is sequentially treated by electrostatic dust removal, activated carbon adsorption, and photocatalytic oxidation to remove dust and VOCs and achieve emission standards.

[0064] Wastewater classification treatment and recycling: The cleaning wastewater and cooling wastewater generated during the processing are sequentially treated by bar filtration, anaerobic digestion, aerobic biochemical treatment, membrane separation and disinfection. The treated wastewater is then recycled for grain cleaning and equipment cooling, realizing closed-loop utilization of water resources.

[0065] Full-process monitoring and parameter optimization: Energy consumption, emissions and water quality parameters are collected in real time through sensors, and process parameters are dynamically adjusted based on a multivariate optimization model to ensure the environmental friendliness and economy of the processing process.

[0066] Preferably, the pretreatment and purification of raw grains specifically includes:

[0067] Stone removal and screening: A gravity destoner is used, with the air volume set to [value missing]. The inclination angle of the sieve surface is Removes stones and large particles from raw grains, improving stone removal efficiency. .

[0068] Airflow sorting: Using an airflow separator, the wind speed is controlled at 8-12 m / s to separate light impurities (such as rice husks and broken leaves) from the raw grain. The sorting efficiency is high. .

[0069] Vibration grading and impurity removal: A vibrating grading screen is used with an amplitude of 5-8 mm and a frequency of 50-70 Hz to further separate medium-sized impurities with a grading accuracy of ≤0.1 mm.

[0070] Magnetic separation for iron removal: Using an electromagnetic separator with a magnetic field strength of 1000-1500 mT, metallic impurities are removed from the raw grain, achieving high iron removal efficiency. .

[0071] Ultraviolet sterilization: Using ultraviolet sterilization equipment with a wavelength of 253.7nm and an irradiation time of 30-60s, microorganisms on the surface of the raw grain are killed, achieving a sterilization rate of [missing information]. .

[0072] The preferred graded low-temperature milling process specifically includes:

[0073] The milling equipment uses a 3-5 stage tandem mill. The milling gaps for each stage are set according to the variety of raw grain and the required processing precision: the first stage coarse milling gap is 0.8-1.2mm to remove the outer rice husk; the second stage medium milling gap is 0.5-0.8mm to remove some rice bran; the third stage fine milling gap is 0.3-0.5mm to further remove rice bran; and the fourth stage ultra-fine milling gap is 0.1-0.3mm (the fifth stage process adds a fifth-stage gap of 0.05-0.1mm) to obtain high-precision coarsely processed rice.

[0074] During the grinding process, the temperature of the grinding chamber is controlled by a water-cooled refrigeration system. This is to avoid high temperatures causing rice starch gelatinization and nutrient loss.

[0075] The mill speed gradient for each stage is set as follows: Speed ​​difference between adjacent stages To reduce the rice breakage rate, the broken rice rate should be controlled below 5%.

[0076] The rice bran produced during the milling process is collected in real time by a negative pressure collection system, achieving high collection efficiency. To prevent dust from spreading.

[0077] Preferred preparation and use of biodegradable and environmentally friendly additives:

[0078] The components and weight parts of the environmentally friendly additives are as follows: 20-30 parts of starch-based polymer, 5-10 parts of tea polyphenols and grape seed extract compound (weight ratio 1:2-3), 10-15 parts of polylactic acid, and 50-60 parts of deionized water.

[0079] Preparation method: Mix starch-based polymer with deionized water, and... Stir and dissolve for 30-60 minutes, then cool to... Then add plant extracts and polylactic acid, and continue stirring for 20-30 minutes to obtain a uniformly dispersed environmentally friendly additive.

[0080] During polishing, environmentally friendly additives are evenly sprayed onto the surface of the coarsely processed rice using a high-pressure spraying device. The amount sprayed is [amount] of the rice's weight. Control the polishing machine speed to Polishing time is 30-60 seconds, and the ambient humidity is [missing information]. The gloss of polished rice And the residual amount of additives .

[0081] Preferably, the recycling and utilization of by-products includes:

[0082] Rice bran processing: Crush the collected rice bran to a particle size of [size missing]. Add a compound enzyme (cellulase, hemicellulase, and amylase in a weight ratio of 1:1:2) for enzymatic hydrolysis. The hydrolysis temperature is... pH value 4.5-5.5, enzymatic hydrolysis time 2-4 hours, the enzymatic hydrolysate is then fermented (inoculated with yeast, fermentation temperature...). After 12-24 hours, the rice bran is concentrated and dried to prepare bio-feed, or biodiesel is prepared through transesterification. The utilization rate of rice bran is [not specified]. .

[0083] Broken rice treatment: Add 3-5 times its weight of deionized water to the broken rice produced during processing. Gelatinize for 30-40 minutes, then cool to... Then spray drying (inlet air temperature) Air outlet temperature ), to prepare rice flour, breakage utilization rate .

[0084] Preferably, the multi-stage synergistic purification treatment of exhaust gas specifically includes:

[0085] Electrostatic precipitator: Dust-laden exhaust gas enters the electrostatic precipitator, which is set at a voltage of 30-50kV. The dust particles become charged and are captured under the influence of the electric field, resulting in a high dust removal efficiency. Dust concentration at the outlet .

[0086] Activated carbon adsorption: The exhaust gas after dust removal enters the activated carbon adsorption tower. Columnar activated carbon is selected, and the adsorption bed space velocity is... It adsorbs VOCs and odor substances in exhaust gas, with an adsorption efficiency of [missing information]. .

[0087] Photocatalytic oxidation: The adsorbed exhaust gas enters the photocatalytic reactor and is then subjected to oxidation. Composite catalyst (weight ratio 3:1), UV irradiation intensity VOCs decompose into VOCs under the action of catalysts and ultraviolet light. and Dust concentration in the exhaust gas after treatment VOCs concentration ≤ It meets the Class I standard of the "Integrated Emission Standard for Air Pollutants" (GB16297-1996).

[0088] The formula used to calculate exhaust emission concentration is: ,in The concentration of pollutants in exhaust gas ( ), The mass (g) of pollutants before adsorption / catalysis. Where is the mass of pollutants after adsorption / catalysis (g), K is the correction factor (value 1.05-1.15), and Q is the exhaust gas flow rate (g). ), t is the treatment time (h), and S is the pollutant conversion factor.

[0089] Preferably, wastewater classification treatment and recycling specifically include:

[0090] Bar screen filtration: Wastewater first passes through a bar screen (pore size 0.5-1mm) to remove large suspended solids, achieving a SS removal rate of [missing information]. .

[0091] Anaerobic digestion: The filtered wastewater enters the anaerobic reactor, and the temperature is controlled. Hydraulic retention time 12-24h, inoculated with anaerobic granular sludge, COD removal rate At the same time, it produces biogas (methane content) It can be used for energy recycling.

[0092] Aerobic biological treatment: Anaerobic effluent enters the MBR reactor, is inoculated with aerobic microbial communities, and the dissolved oxygen concentration is controlled. Hydraulic retention time 8-12h, COD removal rate Membrane flux controlled at .

[0093] Membrane separation and disinfection: After the MBR effluent is separated by an ultrafiltration membrane (molecular weight cutoff 10,000-30,000 Da), it is disinfected by ultraviolet light (wavelength 253.7 nm, irradiation dose). Wastewater after treatment , ammonia nitrogen It meets the "Standards for Irrigation Water Quality" (GB5084-2021) and is recycled for grain washing and equipment cooling, with a wastewater reuse rate of [missing information]. .

[0094] The COD removal rate formula is used to evaluate the effectiveness of wastewater treatment:

[0095] ,

[0096] in, COD removal rate ( ), The influent COD concentration is (mg / L). Where is the effluent COD concentration (mg / L), k is the reaction kinetic coefficient (value range 0.05-0.1), and T is the actual treatment temperature (mg / L). ), Reference processing temperature ( ).

[0097] Preferred approach: Full-process monitoring and parameter optimization.

[0098] Energy consumption sensors, temperature sensors, pressure sensors, dust concentration sensors, and online water quality monitors are installed in the grinding equipment, polishing machine, exhaust gas treatment system, and wastewater treatment system to collect E (energy consumption), T (temperature), and P (pressure) data in real time. Parameters such as dust concentration and COD.

[0099] The process parameters are dynamically adjusted based on a multivariate optimization model. The model formula is:

[0100]

[0101] Where E is the optimized unit product energy consumption ( ), The initial energy consumption baseline value (value) ), Weighting coefficients ( , , ), To improve grinding efficiency ( ), The benchmark grinding efficiency (value) T is the actual grinding temperature. ), For the optimal grinding temperature ( P represents the actual grinding pressure (MPa). The reference grinding pressure is 0.3 MPa.

[0102] The PLC control system enables automatic adjustment of parameters, ensuring that energy consumption and emissions are always at their optimal levels during the processing.

[0103] To better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0104] Example 1

[0105] A green and environmentally friendly processing method for low-emission rice, the specific steps of which are as follows:

[0106] Raw grain pretreatment and purification: Select 1000kg of high-quality rice, and sequentially perform cleaning and stone removal (air volume) sieve inclination angle The process involved airflow screening (wind speed 10 m / s), vibration grading for impurity removal (amplitude 6 mm, frequency 60 Hz), magnetic separation for iron removal (magnetic field strength 1200 mT), and ultraviolet sterilization (wavelength 253.7 nm, irradiation time 45 s), yielding 980 kg of purified grain with an impurity removal rate of [percentage missing]. .

[0107] Staged low-temperature grinding: A four-stage grinding mill is used, with grinding gaps of 1.0mm, 0.6mm, 0.4mm, and 0.2mm respectively for each stage. The grinding chamber temperature is controlled at... The rotation speeds were successively 1200 r / min, 1400 r / min, 1600 r / min, and 1800 r / min. After milling, 780 kg of coarsely processed rice was obtained, with a broken rice rate of [missing information]. 190 kg of rice bran was collected.

[0108] Environmentally friendly polishing treatment: Preparation of environmentally friendly additives (25 parts starch-based polymer, 8 parts tea polyphenol-grape seed extract compound, 12 parts polylactic acid, 55 parts deionized water), based on the weight of rice. The appropriate amount of spray is applied to the surface of coarsely processed rice, and the spraying time is 45 seconds at a rotation speed of 1000 r / min and a humidity of [missing information]. Polishing under these conditions yielded 770 kg of refined rice with a gloss level of [missing information]. The residual amount of the additive is 0.008 mg / kg.

[0109] By-product recycling: 190kg of rice bran was crushed and then enzymatically hydrolyzed with a compound enzyme (temperature). (pH 5.0, time 3h), 150kg of biological feed was prepared after fermentation of the enzymatic hydrolysate; 35kg of broken rice was gelatinized and spray-dried to prepare 30kg of rice flour, with a by-product utilization rate of [missing information]. .

[0110] Multi-stage synergistic purification of exhaust gas: The dust-laden exhaust gas generated during the processing is sequentially treated by electrostatic dust removal (40kV) and activated carbon adsorption (space velocity). ), photocatalytic oxidation ( Composite catalyst, ultraviolet light intensity The dust concentration in the exhaust gas after treatment is [not specified]. VOCs concentration Emissions meet standards.

[0111] Wastewater classification treatment and recycling: 800L of wastewater is generated during the processing, which is sequentially filtered through a screen and then anaerobic digested (temperature). The process involves several steps: 18-hour retention time, aerobic biochemical treatment (MBR process, dissolved oxygen 3 mg / L, retention time 10 h), membrane separation, and disinfection. The treated wastewater has a COD of 45 mg / L and SS of 8 mg / L, and is recycled for grain washing and equipment cooling, achieving a high reuse rate. .

[0112] Full-process monitoring and parameter optimization: Parameters are collected in real time through sensors, and the milling temperature and pressure are adjusted based on a multivariate optimization model. The energy consumption per unit product is 55 kWh / t, which is lower than that of traditional processes. .

[0113] Example 2

[0114] A green and environmentally friendly processing method for low-emission rice, with the following specific steps:

[0115] Raw grain pretreatment and purification: Select 2000kg of high-quality rice, and sequentially perform cleaning and stone removal (air volume) sieve inclination angle The purification process involved airflow screening (wind speed 11 m / s), vibration grading for impurity removal (amplitude 7 mm, frequency 65 Hz), magnetic separation for iron removal (magnetic field strength 1300 mT), and ultraviolet sterilization (wavelength 253.7 nm, irradiation time 50 s), yielding 1950 kg of purified grain with an impurity removal rate of [percentage missing]. .

[0116] Staged low-temperature grinding: A 5-stage grinding mill is used, with grinding gaps of 1.1mm, 0.7mm, 0.4mm, 0.2mm, and 0.08mm respectively. The grinding chamber temperature is controlled at... The rotation speeds were successively 1300 r / min, 1500 r / min, 1600 r / min, 1700 r / min, and 1800 r / min. After milling, 1550 kg of coarsely processed rice was obtained, with a broken rice rate of [missing information]. 380 kg of rice bran were collected.

[0117] Environmentally friendly polishing treatment: Preparation of environmentally friendly additives (28 parts starch-based polymer, 9 parts tea polyphenol-grape seed extract compound, 14 parts polylactic acid, 59 parts deionized water), based on the weight of rice. The appropriate amount of spray is applied to the surface of coarsely processed rice, and the spraying time is 50 seconds at a rotation speed of 1100 r / min and a humidity of [missing information]. Polishing under these conditions yielded 1530 kg of finely processed rice with a gloss level of [missing information]. The residual amount of the additive is 0.007 mg / kg.

[0118] By-product resource recycling: 380 kg of rice bran was enzymatically hydrolyzed and fermented to produce 85 kg of biodiesel; 65 kg of broken rice was processed to produce 58 kg of rice flour. The utilization rate of by-products was [missing information]. .

[0119] Multi-stage synergistic purification of exhaust gas: Exhaust gas undergoes electrostatic dust removal (45kV) and activated carbon adsorption (space velocity... Photocatalytic oxidation (ultraviolet light intensity) The dust concentration in the exhaust gas after treatment is [not specified]. VOCs concentration .

[0120] Wastewater classification treatment and recycling: 1500L of wastewater was generated, and after treatment, COD was 42mg / L and SS was 7mg / L, with a recycling rate of [missing information]. .

[0121] Full-process monitoring and parameter optimization: The energy consumption per unit product is 53 kWh / t, which is lower than that of traditional processes. .

[0122] As can be seen from the above embodiments, the low-emission green and environmentally friendly rice processing method of this application can achieve low emissions of dust and wastewater and efficient utilization of resources, combining environmental protection and economy, and is suitable for large-scale rice processing production.

[0123] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects:

[0124] Significant low emission advantages: Through staged low-temperature grinding, negative pressure dust collection, and multi-stage synergistic purification of exhaust gas, the dust emission concentration is significantly reduced. VOCs emission concentration The efficiency is far lower than that of traditional processes; wastewater is recycled and reused after graded treatment, with a high reuse rate. There is almost no wastewater discharge, resulting in significant environmental benefits.

[0125] Energy consumption is significantly reduced: By adopting graded milling gradient parameter design, low-temperature milling temperature control technology, and a multivariate energy consumption optimization model, the energy consumption per unit product is reduced. The above, from the traditional Down to The energy-saving effect is obvious.

[0126] High resource utilization rate: By-products such as rice bran and broken rice are processed into high-value-added products, achieving high utilization rate. This will help avoid resource waste and improve the economic efficiency of the processing industry.

[0127] Food safety is guaranteed: Biodegradable and environmentally friendly additives are used instead of traditional chemical polishing agents, resulting in minimal additive residue. Furthermore, the processing is carried out at low temperatures to prevent the loss of nutrients and ensure the quality and safety of the rice.

[0128] Highly adaptable to different processes: The milling gap, speed, and polishing parameters can be flexibly adjusted according to different grain varieties and processing precision requirements, making it suitable for large-scale, standardized green rice processing production.

[0129] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A green and eco-friendly processing method of low emission rice, characterized by, The method comprises the following steps: Pretreatment and purification of raw grains to remove impurities and harmful substances; Grinding the pretreated raw grains by a staged low-temperature grinding process to obtain rough processed rice; Polishing the rough processed rice with biodegradable and environmentally friendly additives to obtain fine processed rice; Recycling and utilizing by-products generated in the grinding and polishing processes; Multi-stage collaborative purification of tail gas generated in the processing to make the tail gas emission meet environmental protection standards; Cyclic reuse of wastewater generated in the processing after staged treatment to realize closed-loop utilization of water resources.

2. The low emission eco-friendly processing method of rice as claimed in claim 1, wherein: The pretreatment and purification specifically comprises: sequentially performing airflow screening, vibration grading impurity removal, magnetic separation iron removal, and ultraviolet sterilization, wherein the airflow screening has a wind speed of 8-12 m / s, the vibration grading has an amplitude of 5-8 mm and a frequency of 50-70 Hz, and the ultraviolet sterilization has a wavelength of 253.7 nm and an irradiation time of 30-60 s.

3. The low emission eco-friendly processing method of rice as claimed in claim 1, wherein: The graded low-temperature grinding process specifically includes: using 3-5 stage grinding equipment, with grinding gaps of 0.8-1.2mm, 0.5-0.8mm, 0.3-0.5mm, and 0.1-0.3mm respectively for each stage; and controlling the grinding chamber temperature during the grinding process using a refrigeration system. The rotational speed gradient for each grinding stage is: Speed ​​difference between adjacent stages .

4. The low emission eco-friendly processing method of rice as claimed in claim 1, wherein: The biodegradable and environmentally friendly additives are composed of the following components by weight: starch-based polymer 20-30 parts, plant extract 5-10 parts, polylactic acid 10-15 parts, and deionized water 50-60 parts, wherein the plant extract is a compound of tea polyphenols and grape seed extract, and the weight ratio of tea polyphenols to grape seed extract is 1:2-3.

5. The low emission eco-friendly processing method of rice as claimed in claim 1, wherein: The recycling and utilization of by-products specifically includes: preparing bio-feed or biodiesel from rice bran through crushing, enzymatic hydrolysis, and fermentation; and preparing rice flour from broken rice through gelatinization and spray drying. The enzymatic hydrolysis process uses a compound of cellulase, hemicellulase, and amylase, and the hydrolysis temperature is [temperature missing]. The pH value is 4.5-5.5, and the enzymatic hydrolysis time is 2-4 hours.

6. The low emission eco-friendly processing of rice as claimed in claim 1, wherein: The multi-stage synergistic purification treatment of the tail gas specifically comprises: sequentially passing through electrostatic precipitation, activated carbon adsorption and photocatalytic oxidation, the voltage of the electrostatic precipitation is 30-50 kV, the space velocity of the activated carbon adsorption layer is , the photocatalytic oxidation adopts a composite catalyst, the ultraviolet light irradiation intensity is , and after the treatment, the dust concentration , the VOCs concentration ≤ , in the tail gas. ​ 7. The low emission eco-friendly processing of rice as claimed in claim 1, wherein: The wastewater staged treatment specifically includes: sequentially passing through bar filtration, anaerobic digestion, aerobic biochemical treatment, membrane separation, and disinfection. The temperature for anaerobic digestion is... The hydraulic retention time is 12-24 hours, and the aerobic biological treatment adopts the MBR process with a membrane flux of [missing information]. Disinfection is carried out using ultraviolet light, and the treated wastewater... , It is used repeatedly for cleaning raw grains and cooling equipment.

8. The low emission eco-friendly processing of rice as claimed in claim 1, wherein: It also includes real-time monitoring of energy consumption and emissions during the processing, collecting energy consumption data, tail gas emission concentration, and wastewater quality parameters of each stage of the process by sensors, dynamically adjusting process parameters based on a multivariate optimization model, and the multivariate optimization model is: ， E is the energy consumption per unit product after optimization, is the initial energy consumption reference value, is the weight coefficient, is the grinding efficiency, is the reference grinding efficiency, T is the actual grinding temperature, is the optimal grinding temperature, P is the actual grinding pressure, is the reference grinding pressure.

9. The low emission eco-friendly processing of rice as claimed in claim 1, wherein: The process parameters of the polishing treatment are: the rotation speed of the polishing machine is 800-1200r / min, the polishing time is 30-60s, the spraying amount of the environmental protection assistant is 0.5-1.5% of the weight of the rice , and the environmental humidity is controlled to be 40-60% during the polishing process .

10. A low emission eco-friendly processing method of rice as claimed in any one of claims 1 to 9, wherein: The raw grain is rice, and the pre-treatment further includes a screening and removing stone step, a specific gravity stone removing machine is used, the air volume of the stone removing machine is , the screen surface inclination angle is , and the stone removing efficiency is ≥ 99%.

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