GB/T 26880-2026Grain and oil storage - Technical specification for in-bin drying (English PDF)

4.1 Warehouse

4.1.1 It meets the basic requirements for grain warehouses in GB/T 29890.

4.1.2 Convenient grain loading and unloading, and smooth exhaust gas discharge.

4.1.3 When using movable air ducts for ventilation, the number, location, and size of doors and windows should facilitate the installation of the movable air ducts.

4.2 Grain

4.2.1 The grains should be fresh, basically free of insects, and free from heat or mold.

4.2.2 The impurity content shall not exceed 1%.

4.2.3 The moisture content and the height of the grain pile shall comply with the provisions of Appendix A.

4.3 Wind Network

4.3.1 It shall comply with the relevant provisions of LS/T 1202.

4.3.2 When the height of the grain pile exceeds 3m, a movable ventilation duct should be installed.

4.3.3 For warehouses where the air path does not meet the requirements for precipitation ventilation, movable air ducts should be added.

4.4 Fan

4.4.1 Each wind network group shall be equipped with one wind turbine.

4.4.2 Select the fan according to the relevant provisions of LS/T 1202, ensuring that the air volume and air pressure meet the drying requirements (the minimum unit ventilation volume should comply with Appendix). (Regulations A).

4.5 Other conditions

4.5.1 The power supply (transformer capacity, power line load capacity, etc.) meets the drying requirements.

4.5.2 Configure a grain condition monitoring and control system that meets the requirements of GB/T 26882.1, and it is advisable to have an automatic ventilation control system or ventilation auxiliary decision-making software.

4.5.3 Configure rain protection facilities for equipment such as fans.

4.5.4 Configure an anemometer (instrument) and a rapid grain moisture content detector.

4.5.5 In areas with high ambient humidity, it is advisable to install auxiliary heating equipment with a maximum heating capacity that can raise the air temperature by 5°C.

4.5.6 When the moisture content of grain is higher than 17%, ozone anti-mold equipment and other corresponding supporting measures should be installed.

5.1 Grain Storage

5.1.1 Prepare for and carry out warehousing work in accordance with the relevant provisions of GB/T 29890.

5.1.2 Grain should be stored in the warehouse starting from one end. Ventilation should begin once a ventilation duct is covered over the grain pile to prevent the grain from becoming lodged in the silo. fever.

5.1.3 Take necessary measures to reduce the accumulation of impurities during the warehousing process.

5.1.4 The time for completing the warehousing should be controlled within 25% of the safe drying period.

5.2.1 Fixed air duct installation

5.2.1.1 Before or during the storage of grain, fixed air ducts shall be installed in accordance with the relevant provisions of LS/T 1202 to ensure that the air ducts do not leak grain.

5.2.1.2 Air distributors in underground ventilation ducts should be equipped with hoods.

5.2.2 Installation of Modular Riser Ventilation Ducts

5.2.2.1 It is advisable to install it after the grain storage operation is completed and the grain surface is leveled.

5.2.2.2 The lower part of the combined riser should have evenly spaced openings in the pipe wall, with appropriate opening sizes (to prevent grain leakage), and the opening area should not be less than the total area of that section. 15%.

5.2.2.3 The spacing between combined risers should be within 1.5m.

5.2.2.4 Before or during ventilation, air ducts can be added to areas of the grain pile where the air path is long and the air volume is small.

5.2.3 Other preparations

5.2.3.1 Deploy temperature measuring cables for the grain condition monitoring and control system in a timely manner.

5.2.3.2 Connect the fan to the duct and prepare for rain protection for the fan, heater and other equipment.

5.3 Drying Operation

5.3.1 Drying should be completed within the safe drying period for grain (see Appendix B for the safe drying period for rice and corn).

5.3.2 On-duty personnel should be arranged to manage the drying operation, and ventilation-assisted decision-making software or automatic ventilation control from the grain condition monitoring and control system should be used. The system manages the drying operation.

5.3.3 On-duty personnel should perform the following tasks daily.

---Inspect the connections between the fan and the duct, and between the ventilation riser and the main duct, to ensure that the duct connections are tight;

---Open or close doors and windows as needed, and turn fans, heaters, and other equipment on or off as needed;

---Check the operation of equipment such as fans and heaters to ensure they are functioning properly;

---Take precautions to protect grain and equipment from rain.

5.3.4 Ventilation is sufficient when the temperature and humidity of the incoming air correspond to a grain equilibrium moisture content that is 1 percentage point lower than the moisture content of the grain to be dried; When the ambient humidity is low, turn on the air conditioner directly for ventilation; when the ambient humidity is high, use an auxiliary heater to reduce the relative humidity of the incoming air.

5.3.5 Autumn drying should be completed before the daily average temperature drops below 10°C, and spring drying should be completed before the daily average temperature reaches 22°C.

5.3.6 When using a combined vertical ventilation system, remove one layer of ventilation pipe after each layer of grain is dried. The system can be adjusted according to the moisture content of the grain pile. The riser is moved to the part of the grain where the moisture content is high and the drying process is slow.

5.3.7 For the middle and lower layers of grain, an upward-flow ventilation drying method is recommended. This should be used when the middle and lower layers of grain are completely dried and the moisture content of the upper layer of grain is not high. When the safe storage moisture content is 1.5%, downward ventilation can be used to dry the upper layer of grain to within the safe storage moisture content.

5.3.8 Once the moisture content of the grain reaches the safe storage requirements, drying and ventilation should be stopped.

5.3.9 For grains with excessively high moisture content, the top layer of the grain pile should be dried during storage, followed by temperature-controlled storage to ensure the grain moisture content matches the corresponding storage temperature. It meets the requirements of GB/T 43994.

5.3.10 During hot seasons or when the outside temperature is significantly higher than the grain temperature, grains with high moisture content can be cooled and dehydrated using a grain cooler throughout the silo. The relative humidity of the air outlet should be 70%~80%, and the outlet air temperature should be 5°C~10°C lower than the grain temperature. Dry and cool air can be achieved using a dedicated dehumidifier or other methods. Local ventilation, cooling, and precipitation are implemented to reduce air temperature.

5.4 Detection and Recording

5.4.1 After the grain is stored in the warehouse, samples should be taken from all grain in the warehouse in a timely manner to test the moisture content and storage quality. The sampling points should be arranged according to... The requirements of GB/T 29890 shall be followed, with moisture content tested at different points and in different layers, and storage quality tested using a comprehensive sample from the entire warehouse.

5.4.2 Temperature and humidity values of the grain pile and the surrounding environment should be measured and recorded at least daily at the first start-up of the blower and the last shut-off of the blower. Daily ventilation time.

5.4.3 The moisture content of the grain should be tested at least once every 24 hours of ventilation using a rapid moisture meter. Spot testing should be set up in areas where drying is faster and slower. For sample testing, the interval between moisture content tests can be appropriately shortened for parts that dry relatively quickly.

5.4.4 During the drying period, the top 20cm-30cm of grain in the grain pile should be checked at least twice a week for compaction. If compaction is found, [further action should be taken]. Turn the grain over regularly.

5.4.5 After drying, all grain samples were taken from the warehouse for moisture content and storage quality testing. Moisture content was tested at different points and layers, and storage quality was tested... Take a comprehensive sample of the entire warehouse. In addition to the sampling points in 5.4.1, the areas that dry the fastest and the areas that dry the slowest should also be added as sampling points.

5.4.6 All tests shall be recorded. The record summary table is attached as Appendix C. The records shall be archived for no less than 3 years.