T/HBLS 0019-2023 in English

Scope

Terms and definitions The terms and definitions defined in GB/T14095 and the following terms and definitions apply to this document. 3.1 Flat vibrating sorting screen A filtering mechanical separation device that processes solids through a horizontally placed vibrating screen. 3.2 Cylindrical sorting screen A filtering mechanical separation device that processes solids through a rotatable cylindrical screen. 4 Basic requirements 4.1 Wet rice entering the machine 4.1.1 The moisture content of wet rice entering the machine should be 16% to 30%. Rice of different varieties and moisture contents should be stored and dried separately. For the moisture unevenness of the same batch of dried rice, the continuous dryer should not be greater than 4 percentage points, and the batch circulation dryer should not be greater than 8 percentage points. 4.1.2 Other quality indicators should comply with the provisions of GB1350 or GB/T17891. 4.2 Dryer and supporting facilities T/HBLS0019—2023 2 4.2.1 Continuous dryers shall comply with the provisions of GB/T16714, and batch circulation dryers shall comply with the provisions of JB/T10268. Supporting equipment shall comply with the provisions of LS/T3501.1. 4.2.2 The dryer shall have a drying layer and a slow-release layer. 4.2.3 The discharge of the dryer shall comply with the provisions of GB/T16714 and JB/T10268. 4.2.4 The supporting equipment of the dryer (conveyor, drying front bin, drying rear bin, etc.) shall comply with the provisions of LS/T3501.1 after commissioning and can be put into use normally. 4.3 Personnel 4.3.1 Positions such as on-site operation inspection of drying operations shall be equipped with fixed personnel. 4.3.2 Operators and managers shall be professionally trained and proficient in the technical specifications and operating procedures for rice drying. 5 Drying technical requirements 5.1 Initial cleaning of rice 5.1.1 The wet rice entering the machine needs to be initially cleaned to remove impurities and debris. After the initial cleaning, the impurity rate shall not exceed 4%, of which straw impurities exceeding 30mm shall not exceed 2%, and there shall be no foreign matter such as long stems, sack ropes, polyethylene films, etc. 5.1.2 According to the moisture content and impurity content of the raw grain, one-stage initial cleaning or two-stage series initial cleaning can be adopted. The initial cleaning equipment can use a plane vibrating screen and a cylindrical screen, and the two-stage series initial cleaning mostly uses a cylindrical screen + a plane vibrating screen. 5.2 Drying conditions 5.2.1 The allowable heating temperature of rice is not more than 40℃. 5.2.2 The precipitation range of one-time drying and slow drying process: when the moisture content of rice is between 22% and 30%, the precipitation range shall not exceed 3 percentage points; when the moisture content of rice is between 18% and 22%, the precipitation range shall not exceed 2 percentage points; when the moisture content of rice is less than 18%, the precipitation range shall not exceed 1 percentage point. 5.2.3 Drying rate: When the moisture content of rice is between 22% and 30%, the drying rate shall not exceed 3 percentage points/h; when the moisture content of rice is between 18% and 22%, the drying rate shall not exceed 1.5 percentage points/h; when the moisture content of rice is less than 18%, the drying rate shall not exceed 0.8 percentage points/h. 5.2.4 Hot air temperature: When the moisture content of rice is between 22% and 30%, the hot air temperature shall be between 60℃ and 90℃; when the moisture content of rice is between 18% and 22%, the hot air temperature shall be between 55℃ and 65℃; when the moisture content of rice is less than 18%, the hot air temperature shall be between 50℃ and 60℃. 5.3 Drying process 5.3.1 Basic drying process: (a) For drying rice with a precipitation amplitude of less than 1 percentage point, the drying process A shown in Figure 1 can be adopted, and a batch circulation dryer or a continuous dryer can be used. Wet rice → drying → slow revival → cooling → dry rice Figure 1 Drying process A (b) When the moisture content of rice is less than 18%, a batch circulation dryer can be used, using process B as shown in Figure 2; a continuous dryer can also be used, using process C as shown in Figure 3. Wet rice → drying → slow revival → (drying → slow revival multiple cycles) → cooling → dry rice Figure 2 Drying process BT/HBLS0019—2023 3 Wet rice → drying → slow revival → (multi-layer drying → slow revival) → cooling → dry rice Figure 3 Drying process C (c) When the moisture content of rice is between 18% and 30%, if a batch circulation dryer is used, process B as shown in Figure 2 is used; if a single continuous dryer is used, process C as shown in Figure 3 is used; a drying process in which a continuous dryer + a batch circulation dryer are combined in series can also be used; a drying process in which multiple batch circulation dryers are combined in series can be used; a drying process in which multiple continuous dryers are combined in series can be used. 5.3.2 Batch circulation dryers can reduce the moisture content to safe or specified moisture content by following the operating procedures of the dryers. 5.3.3 Continuous dryers can reduce the moisture content to safe or specified moisture content by following the operating procedures of the dryers. 5.3.4 For small batches of rice with multiple varieties, it is advisable to use a single batch circulation dryer or multiple batch circulation dryers in parallel. 5.3.5 For large batches of rice with a single variety, it is advisable to use multiple batch circulation dryers in parallel, multiple batch circulation dryers in series, or continuous dryers. 5.3.6 For large batches of rice with a moisture content of more than 22% and insufficient mechanical drying capacity, it is advisable to use a continuous dryer + batch circulation dryer in series: (a) Use a continuous dryer for rapid pre-dehydration to reduce the moisture content to 20% ± 2%, using the process specified in 5.3.1. (b) Transport the pre-dehydrated rice to the batch circulation dryer for dehydration through conveying equipment. 5.3.7 For large-scale rice drying operations where the moisture content of wet rice entering the machine is greater than 22% and the mechanical drying capacity is seriously insufficient, it is advisable to use a combination of mechanical drying and in-storage drying in series: (a) Mechanically dry the high-moisture rice to reduce the moisture content to 18%-20%, using the process specified in 5.3.1 or 5.3.6. (b) Send the rice to a temporary storage warehouse for in-storage drying in accordance with the provisions of GB/T26880. (c) After the rice harvest season is over, mechanically dry it to a safe moisture content or a specified moisture content, using the process specified in 5.3.1. 5.4 Drying process requirements 5.4.1 Drying and revival process requirements: The ratio of drying time to revival time for continuous dryers is 1:2-1:4; the ratio of drying time to revival time for batch circulation dryers is 1:3-1:6. 5.4.2 Cooling process requirements (a) If the ambient temperature is not greater than 0℃, the cooling air volume per ton of rice is less than 800m3/h. (b) If the ambient temperature is greater than 0℃, the cooling air volume per ton of rice is less than 1000m3/h. (c) If the ambient temperature is greater than 32℃, the cooling process can be omitted. (d) If the grain is temporarily stored in a ventilated bin after drying, the cooling process can be set in the ventilated bin. (e) If the grain is dried in the bin after drying, the cooling process can be omitted. 6 Safety Technical Requirements 6.1 When the dryer is in operation, operators should strictly prohibit entering the dangerous areas and dangerous parts warned by the safety signs; it is strictly prohibited to disassemble and install safety protection devices and safety devices; it is strictly prohibited to open the dryer maintenance door; no one is allowed to enter the pre-drying bin, slow recovery bin, post-drying bin and the grain storage section of the dryer. 6.2 Safety belts and safety helmets should be equipped for high-altitude fault handling. 6.3 The electrical control room should have full-time personnel for operation and management, and strictly implement electrical safety operating procedures. T/HBLS0019—2023 4 6.4 The dryer should be shut down regularly according to the instruction manual, all the rice should be emptied, and all the dust, stems and other residues in the machine and the chute should be cleaned. 6.5 The heating system should be implemented according to the operating procedures of the equipment. 7 Quality of rice after drying and quality of drying operation 7.1 The quality of rice after drying should meet the requirements of Table 1. Table 1 Quality indicators of rice after drying Item Index Value Moisture Safe moisture or specified moisture Drying unevenness/percentage point ≤1.0 Broken rate Increased value/percentage point ≤0.3 Color and odor Normal Severe crack rate (burst) Increased value/percentage point ≤3.0 Impurity content/%≤2 Grain discharge temperature/℃≤ambient temperature+8 7.2 The quality of drying operation should meet the requirements of Table 2. Table 2 Quality of drying operation Drying method Continuous dryer Batch circulating dryer Heat consumption of dryer / (kJ/kg precipitation) Direct heating ≤5000 Indirect heating ≤8800 Direct heating ≤5800 Indirect heating ≤8120 Large impurity removal rate / %100 Small impurity removal rate / %≥80 Light impurity removal rate / %≥90 Grain content of large and small impurities (full grains) / % - Grain content of light impurities (full grains) / % -7.3 The collection of rice samples before and after drying shall be carried out in accordance with the provisions of GB/T5491, and the inspection method shall be carried out in accordance with the provisions of GB/T5492, GB/T5494, GB/T5496, GB/T5497, GB/T5498 and GB/T6970.