In the production process of the pellet feed cooling section, it is necessary to ensure that the moisture content of the pellet feed after cooling is in compliance with the requirements for safe storage. How to effectively control the moisture content of pellet feed, in addition to the importance of the cooling process, there are many other factors that affect the moisture content of the pellets. In the particle cooling process, it is essential to select efficient cooling equipment and a reasonable wind network. In addition, the moisture content and the amount of steam in the raw material before granulation and the granulation process must be strictly controlled, so as to ensure that the moisture content of the finished pellet feed meets the quality index. The authors elaborated on the main factors for selecting the equipment for the cooling process and removing the moisture affecting the pellets, which are only for reference by the pellet feed manufacturers. In the granulation process, the material must be tempered by high-temperature steam, and the material is strongly extruded through the die, so that the granules can reach a temperature of about 85 °C and a moisture content of about 15%. In this case, the particles are easily broken and the storage is prone to mildew. Therefore, the high-temperature, high-humidity particles after granulation must be subjected to moist heat transfer through cooling treatment, and the surface water and heat added by the steam must be diffused in time to cool the pellets to a temperature not higher than 5 ° C and the moisture content is reduced to 12%-15%. Left and right, this can not only increase the hardness of the particles, but also facilitate the transportation and storage of the pellets, and also improve the quality of the finished pellets.
1. Choose a suitable cooler and configure a reasonable wind network:
The counterflow coolers widely used in feed mills are advanced cooling equipment used internationally in the 1990s. After cooling by the counter-flow cooler, the pellet temperature is lower than room temperature 3-5 °C, and the precipitation rate is higher than 3.5%. After the particles are cooled, the surface is as follows, without cracks, and the appearance is smooth, which is good for sales, transportation and storage. The cooler adopts a cooling air flow and a relatively flow form of the flow, that is, the ambient cold air vertically passes through the granular material layer from the bottom, first contacts the cold particles, and then the hot air which gradually becomes hot contacts the hot particles. Because the direction of the wind flow is opposite to the direction of the flow, the pellets are gradually cooled in the forward direction, which can avoid the direct cracking of the particles caused by the rapid cooling of the vertical cooler due to the cold wind and the high-temperature pellets. Since the cold air enters the cooler from the bottom in all directions, the air inlet area is large, and the cold air utilization rate is high, so the cooling effect is remarkable, the energy consumption is low, the operation is simple, and the automation degree is high.
The cooling air network is an indispensable auxiliary system for the cooling equipment, and its structure is more reasonable than the impact of the cooling equipment. In the feed mill, cooling ducts, dust collectors are blocked, the air outlets are run, and the condensed water in the winter is reversed. The design or installation of the cooling air network is unreasonable. Therefore, when using a counterflow cooler, an effective wind screen system must be designed in accordance with the relevant data provided in the equipment manual. The wind network system is an indispensable device for providing cooling air sources. It is mainly composed of a dust collector, a wind deflector, a fan and a duct. After cooling the air network configuration, to ensure good use, you should pay attention to the following points:
(1) Reduce the length of the entire wind network system as much as possible, reduce the number of heads, prevent the deposition of powder in the pipeline, avoid excessive pressure loss and reduce the air volume, and affect the cooling effect.
(2) Reduce the length of the horizontal duct as much as possible to prevent condensation. In particular, in the winter, the insulation material can be wrapped in a suitable position to reduce the generation of condensed water, and the resulting powder clogging the air duct.
(3) Reasonably select the wind speed and adjust the wind speed. An air volume adjustment device should be installed on the pipeline to adjust the air volume so that the steam is condensed out of the room.
(4) Reasonably design the diameter of the duct so that there is sufficient wind speed inside the tube. Generally, the wind speed in the air duct should be 13-16m/s. If it is less than 12m/s, the dust in the air duct will easily accumulate in the pipe, and it is easy to produce condensed water.
(5) The whole wind network system should adopt the suction type, that is, work under the negative pressure state, and the fan is placed behind the dust collector, so that the fan blades will not absorb the humid dust, ensure the working environment of the fan, avoid causing the vibration of the fan, and increase noise.
(6) The use of special dust collectors and cooling fans should be considered for easy cleaning in the design and installation of ducts. In order to ensure the quality of pellet feed, in addition to selecting a suitable cooler, it is necessary to strictly control the moisture of the raw materials before granulation, the quality of steam during granulation and the amount of steam added.
2. Control raw material moisture:
At present, in the pellet feed processing process, a cooler is used to reduce the moisture and heat added by the finished pellets due to the high temperature steam quenching during the granulation process, so that the moisture of the finished pellets is returned to the original moisture content before granulation. . The pellet feed is carefully processed from a variety of raw materials through scientific formula, and the raw moisture of the raw material is undoubtedly reflected on the finished pellets. When the moisture content of the raw materials exceeds the standard, the processing technology of the general feed mill, if it is not cooled after drying, cannot solve the problem that the moisture of the finished pellets exceeds the standard due to the excessive moisture of the raw materials. To ensure that the moisture content of the pellets meets the quality specifications, the moisture of the raw materials must first be controlled. Corn accounts for a large proportion of compound feed, and its standard moisture is higher than the standard moisture of the compound feed, so it is important to control the water content of the corn in the raw material. Therefore, when the feed mill organizes the procurement of raw materials, in addition to testing the main nutritional indicators, we must also pay attention to the detection of moisture content. If the raw material moisture exceeds the standard, it must be treated by other methods before granulation to make the moisture content meet the quality requirements. Only by strictly controlling the moisture content of various raw materials can the final quality of the finished pellets be safely stored.
3. Control steam quality:
The quality and amount of steam directly affects the moisture content of the finished product, but is ignored by many feed mills. Granulation is suitable for dry saturated steam and should not be accompanied by condensed water. A suitable vapor pressure is generally from 0.2 to 0.4 MPa. The steam pressure remains basically stable, and the pressure fluctuation amplitude should generally not exceed 0.15 MPa. In order to ensure that no condensed water enters the quenching and tempering system, the boiler room should be as close as possible to the main workshop. The boiler room and the main workshop are all equipped with buffer cylinders. The steam is delivered by high pressure and an automatic drain is placed in the duct and at the bottom of the cylinder. The main shop steam separator should not be too far apart from the granulator. The return pipe should be arranged vertically, and the steam trap and drain valve should be connected below to effectively remove the condensate. The control of steam quality has a great influence on the moisture content of the particles. The steam system that meets the requirements can achieve twice the result with half the effort. In short, feed mills should constantly explore and summarize experiences in the production process. Only by properly and effectively controlling the quality of steam can we control moisture and improve the quality of finished pellets.
Poultry House
Poultry House,Angola Poultry House,Poultry Broiler House
Steel Structure Workshop Co., Ltd. , http://www.nssteelstructure.com