Application of Pellet Cooling Machine in the Processing of 1-100 Ton Per Hour Animal Feed Pellet Production Plant
The processing equipment serves the feed line production process and is the concrete executor of the reasonable production process. With the continuous improvement and improvement of the level of feed processing technology, the performance requirements of animal feed processing equipment are also more stringent. This not only refers to the traditional host equipment, such as animal feed hammer mill crushers,animal feed mixing machie and animal feed pelletizers, but also includes such as feed pellet coolers, dryers, stabilizers (post-curing) and spraying machines. At present, quite complete auxiliary processing equipment is used in the relatively reasonable and complete feed processing technological process, which has a non-negligible impact on the finished feed product. Today, Richi Machinery is here to talk to you about the application of coolers in animal feed mill factory processing.
In animal feed making plants, most of the feed production processes use animal feed pellet mill machine to produce animal pellet feed. The pellets just produced from the feed pelletizer machine have a temperature of about 85°C and a moisture content of 13% to 17%. At this time, the feed pellets are fragile and should be cooled and dewatered in time to reduce their temperature to close to room temperature (about higher than room temperature). 3℃～5℃), the water content is reduced to 12%～13% (i.e. safe storage water), making it convenient for crushing, storage and transportation. The cooler is usually used to perform this process.
At present, there are mainly three types of coolers used in animal feed manufacturing plant: vertical, horizontal and counter-current. With its advantages of high degree of automation, small footprint, small air suction, and low power consumption, the counterflow cooler quickly replaced the other two coolers as the current mainstream product and is widely used by feed mill companies.
The countercurrent cooler uses the principle of countercurrent cooling to cool high-temperature and high-humidity pellets. The equipment is mainly composed of closed-air feeders, bulkers, cooling bins, unloading devices and other components. According to the different structure of the unloading device, there are many derivative series. The two currently more mature unloading devices are the sliding gate discharge mechanism and the flap discharge mechanism (also known as the "rotating valve discharge mechanism"). The counterflow SKLN series cooler produced by Richi Machinery adopts a sliding gate discharge mechanism.
In the process of use, the counterflow cooling machine should consider the following issues in order to facilitate the operation of the equipment in an efficient and economical state.
1. Airflow status
For counterflow coolers, the most important airflow parameters are: air volume, air pressure and wind speed.
The heat and moisture in the pellet feed are taken away by the air medium, and there is enough air volume to ensure the output of the countercurrent cooler. See Table 1 for the reference cooling air volume for different specifications of pellet feed.
Table 1: Pellet feed cooling time and reference air volume
|Pellet size (mm)||Cooling time(min)||Reference air volume (m3/min•t)|
Normally, our SKLN series coolers are equipped with fans according to the reference air volume of φ12 mm specifications.
When cooling, it is very important to determine a reasonable wind speed range. Under normal circumstances, 1.8m/sec is a generally accepted indicator. At the same time, the wind speed in the suction pipe should be 13-16 m/sec. In the conventional sliding gate counterflow cooler, excessive wind speed will cause agglomeration, arching and uneven discharge, and will also cause the material bed to "fluidize", resulting in inconsistent cooling effects due to the different residence time of materials in different parts . In addition, controlling the wind speed can effectively avoid creating a "wind tunnel" on the material bed, preventing short circuit of the air flow and affecting the cooling effect.
Under normal circumstances, the thickness of the material layer of the SKLN series cooler is between 0.7m and 1.1m, and the recommended air pressure should be ≥200mmH2O.
2. The discharge port area of the counterflow pellet cooler
Comprehensive consideration of the cooling air volume per unit pellet feed and the maximum wind speed can determine the maximum output of a certain type of counter-flow cooler. Therefore, in order to obtain higher output, the cooling air volume should be increased, and at the same time, the area of the discharge system should be increased accordingly. The discharge ports of SKLN series coolers are all square. This design has a better ground space utilization rate than the circular silo counterflow cooler of the same size, and the production capacity is increased by 28%. This is also the reason why SKLN series coolers have greater cooling capacity.
3. Prevent arching and agglomeration
The higher the output of the cooling operation, the greater the air volume required. For a counter-flow cooler, this means an increase in the probability of arching and agglomeration. If a counter-flow cooler with a larger output is to be obtained, the discharge device must meet certain requirements, that is, the larger air volume and Under the premise of higher wind pressure, it can still discharge uniformly and reliably. There is no obvious difference between the smaller size sliding grid and the flap counterflow cooler in this respect, but when the cooling output is large or when the pellet feed is easy to build up, it has certain advantages as an improved flap counterflow cooler. When discharging, one end of the flap is lifted up to break the arch, thereby effectively preventing the arching and agglomeration that may occur in the sliding gate discharge mechanism.
4. Some suggestions
Some data show that the higher the water content of the feed pellets, the faster the water evaporation rate and the better the cooling effect. Analyzing the reasons, it is not difficult to see that the evaporation of water requires heat, and it is the feed pellets that provide heat in the cooler, which is exactly what the cooling process wants. Therefore, within the allowable range, consideration should be given to appropriately increasing the feed moisture, which is conducive to increasing the output of the cooler.
5. RICHI SKLN series cooler machine
We produce a wide range of counter current cooler machines that are used for the cooling of the pellet. The pelleted product goes from a temperature higher than 60°C to approximately +5°C in respect to the room temperature.
（1）Technical characteristics of our cooling machines:
①Frame made of alloy section bars, with appropriate dimensions.
②Stainless steel aspiration hood with opening that can be positioned on every side of the cooler.
③Stainless steel case complete with inspection door and minimum and maximum level indicators.
Min. level indicator height can be adjusted to enable the right product inflow into the case.
④Product extraction unit operated by micro reduction gear with brake.
⑤Stainless steel star valve with gear motor to adjust product inflow into the case.
⑥Discharging hopper to collect the product under the cooler.
⑦In case of anomalous stop of the extractor, a product discharging device with three ways of working, is foreseen.
①If required the machine can be supplied with building specification observing ATEX Ex II 3D regulations.
②Thermostat for fire prevention.
③Intermediate shutter for quick change of the product without stopping the system.
（3）Beside the coolers, following machines are in a complete animal feed pelletizing line: