Selection principles for P-series two-stage pusher centrifuges

Thread Content

There are a wide variety of separation machinery, with different types and specifications, as well as varying structures and performances. The types and properties of the materials being processed also vary. Every user hopes to obtain a separation device that can meet the requirements of their own enterprise’s production processes and operate effectively over the long term. Therefore, it is particularly important to carry out thorough and scientific selection work. If the selection is improper, not only will the requirements not be met, but it may also lead to failure and halt production, resulting in significant economic losses. Separation is an operational unit in a chemical processing process; therefore, when selecting separation equipment, it is necessary to fully consider the compatibility between the equipment and the process flow. It is important to determine the properties of the materials to be separated, as well as the requirements regarding feed volume and output volume, and to define the technical specifications for the final product. At the same time, the impact of the process flow on the characteristics of the materials must also be taken into account. Users are required to provide representative samples to fully demonstrate the properties of their material. At the same time, the conditions of the process should be changed to the greatest extent possible, so that the material can fully adapt to the selected separation equipment. Users should learn as much as possible about the performance and features of separation equipment when making a selection. If a choice is made by simply following the examples of similar companies, equipment failure may occur due to differences in specific conditions. By failure is not meant merely the inability of a device to operate; it also includes the situation where the selected device fails to meet the desired objectives, such as insufficient production capacity or products that do not meet the required standards after separation. In accordance with international practices, our company designs separation equipment tailored to the specific needs of each customer. It is essential for customers to fill out the \"Customer Process Survey Form\" thoroughly and in detail; this is a prerequisite for ensuring a personalized design as well as optimal performance of the selected equipment. Before deciding to use a P-series two-stage pusher centrifuge, the user should provide the following process parameters: a) Properties of the solid phase, including its chemical composition and concentration ； Particle size, distribution ； The shape, density, sedimentation properties, hardness, etc. of the particles ； b) Liquid properties include chemical composition, density, temperature, viscosity, pH value, etc ； c) Requirements for the separation process, including processing capacity and purpose of treatment ； Washing and filtration properties of the solid phase ； Requirements for the separation of solid and liquid phases ； d) Other requirements include the crystal surface, recommended materials, electrical and automation control, etc. 　　The P-series pusher centrifuge is a high-speed filtration centrifuge. When selecting this type of machine, in addition to taking full account of the enterprise’s processing requirements and the suitability of the machine, users should also pay attention to the following points: ① The P-series pusher centrifuge is suitable for separating suspensions with medium and large particle sizes; it can also be used to separate suspensions containing fibers. The scope of its application is shown in Figure 1. If the particles of the material are too fine, the filtering efficiency decreases, the processing capacity is reduced, and the solid content in the mother liquor becomes high, which is not favorable for production. In such cases, the process conditions should be improved as much as possible to promote the growth of particle size, thereby reducing the solid content in the mother liquor. ② Pusher centrifuges fall under the category of filter cake filtration; therefore, they are suitable for suspensions with high concentrations, and the solid-to-liquid ratio should preferably be greater than 1:1. When the suspension is too dilute, it is not possible to form a filter cake inside the drum, thereby preventing proper separation and discharge of the material ； In severe cases, it can even cause the drum to lose balance, resulting in vibrations that affect the machine’s service life. Therefore, when the concentration of the suspension is too low, pre-thickening measures must be taken to increase the concentration of the material entering the centrifuge. It should be noted in particular that the pusher centrifuge is also quite sensitive to fluctuations in the suspension concentration. Unstable feeding can easily cause vibration in the machine, and may even damage it. Therefore, to ensure the proper operation of the machine, the concentration of the suspension and the feeding rate must be kept stable. ③ When selecting P-series pusher centrifuges, users should fully consider the impact of the technical parameters of the screen on the machine’s performance. The screens used in the P-series pusher centrifuges manufactured by our company are produced using advanced technology. The main technical parameters of these screens are the gap width S and the spacing K; they have a direct impact on the residual moisture content of the filter cake as well as the solid content in the filtrate. Here, we would like to emphasize that the particle size of the solids being processed, the viscosity of the mother liquor, the solid content in the slurry, and the uniformity of the feed all have a significant impact on the productivity of the centrifuge. They also affect the loss of fine particles during the filtration process (leading to an increase in the solid content in the liquid) as well as the moisture content of the solids after separation. The uneven feeding will also cause the machine to vibrate, thereby damaging its components and having a direct impact on the service life of the centrifuge. To this end, we ask customers to approach the completion of the material survey form with full seriousness. 　　Our company currently has five models of two-stage pusher centrifuges: P-40, P-500, P-60, P-85, and P-100. Apart from differences in drum diameter, production capacity, and separation factors, their screen lengths also vary ； That is, the residence time of the materials inside the drum also varies. Users should select different models of centrifuges based on actual conditions and specific requirements. Since the number of pushes by the pusher centrifuge and the speed of the drum directly affect the machine’s production capacity as well as the technical parameters of the solids to be separated, special attention must be paid when selecting such equipment. Advanced international process calculation software can provide recommended technical parameters based on the \"process questionnaire\" filled out by the user, thereby **reducing the technical risks associated with equipment selection.