How to pump dry substances in an energy-efficient manner One of the processes in the production of pulp and paper is the production of raw materials, which are almost dry substances. Raw material handling can account for up to 20% of the paper mill's total energy needs and must be diluted to the proper concentration before being pumped. Reijo Vesala of Sulzer Pumps discusses this special pump, mixer and other equipment that not only ensures reliable handling and tower management at pulp and paper mills, but also reduces energy consumption levels. Figure 1. Paper mill pulp: The pulp and paper industry processes materials with high solids content. Sulzer Pump offers a full range of products to meet the pumping needs of medium-strength raw materials. Figure 2. Typical O2 water erosion and bleaching process at a chemical pulp mill. Sulzer Pumps manufactures equipment that meets the needs of all pumping and mixing equipment and increases process efficiency through stable and reliable operation. Figure 3. Sulzer's medium-density pumps cover all paper and paper mill lift and flow combinations with heads up to 240 meters and flow rates of 20-5000 ADt / d (dry tons / day). Figure 4. Typical MC® Pumping Equipment: Feed levels in the drop-leg are measured and controlled to provide continuous pump operating conditions. Raw material pumping is one of the most important operations in pulp and paper production. The feedstock is pumped from a different vessel, such as a storage tower, reaction tower, and scrubber, to a subsequent treatment stage. The raw material concentration or the weight ratio of solid matter can be as high as 35%. Depending on the process and the stage of treatment, medium and high concentrations of suspended solids may contain chemicals and abrasive media that require efficient, dedicated machinery. Many processes in pulp and paper mills include the pumping of raw materials (Figure 1). The amount of energy required to pump raw materials can represent up to 20% of the plant's total energy consumption. Dry, high solids feedstocks may be thick enough to support one's weight. Raw materials of this nature must be liquefied before being pumped. For maximum efficiency, any air that may be present in the pulp suspension must first be removed. If too much free air is contained in the feedstock, pumping efficiency will be reduced unless the design of the pump allows for this limitation. During the wash and bleach stages of the production process, the feedstock concentration typically increases from a low concentration range (0-8%) to a medium concentration range (8-18%). Depending on the process, the concentration range is generally 4-16%. The concentration may exceed 30% during the deinking and mechanical pulping of recycled fibers and in the chemical slurry washing stage. After the raw material is dispersed, bleached and washed, it is diluted to a suitable concentration for pumping. In the chemical pulp bleaching and previous stages, the pressure in the pump inlet section can be very high and the temperature can reach 130 ° C (Figure 2). Bleach liquids and other process chemicals are mixed into the feedstock at the same time during this phase. Concentration range Sulzer pump products can be used in a wide range of product concentrations. The Ahlstar UP feed pump is available in a lower concentration range (Figure 3). In the high-end concentration range, the highly efficient MCETM pumping system is used to handle the highest concentration of fluid that can be pumped using a centrifugal pump. The Sulzer LCETM and KCETM pumping systems are coming to the market with an efficient pumping solution specifically designed for use in the semi-MCTM concentration range (6-10%). Before these products were introduced, manufacturers had to use low-concentration feed pumps or pumping systems for the pumping of medium-strength feedstocks. As a result, Sulzer Pumps has developed and introduced an energy-efficient and fiber-protected pumping solution specifically designed to meet the needs of medium-strength raw materials. The energy requirements of these systems are far lower than traditional products. Most of this new solution consists of a pumping system and a drive unit, with a simpler design than the previous product. Patented technology Sulzer's pump for medium-strength material has a specially designed impeller and is a patented FluiderTM technology. Pump systems with Fluider technology are mostly used in scrubbers, thickeners, filters and reaction columns to pump raw materials to the next process stage. The pumping system also helps to ensure bleach liquids or process chemicals are effectively mixed into the feedstock. Key benefits of this technology include energy efficiency, which reduces energy consumption and the ability to maintain precise eddy current levels to prevent over-processing of the fibers. Medium-duty pumps typically have a built-in or external outgassing system driven by a high-flow vacuum pump. The Fluider impeller also offers a third option: Degassing is also possible without a vacuum pump, a solution that does not require additional components or controls and drives. Another unique feature of this Fluider impeller is that it operates efficiently regardless of the concentration of material in the drop-leg (Figure 4). (Drop-leg is a barrel tank on the low pressure side of the pump that ensures proper pump in.) Savings and Upgrades Fluider Technology Improves Productivity and Improves Productivity Through Installation in Refurbished Equipment or Replacement of Existing MC® Pumps Process upgrade. In most cases you do not even need to change the pipe. Modern Salomix? Tank blenders with high propulsion efficiency. In addition, Dilco technology allows for the use of less energy-intensive areas at the bottom of the tower (Figure 5). Tower Management Friction between stationary and moving pulp in a storage tower can lead to an uneven concentration distribution, leading to increased concentration of stationary pulp and dilution of moving pulp. Differences in concentration lead to unbalanced residence times, ie, shorter residence time for moving pulp and longer residence time for still pulp, resulting in lower product quality. Sulzer's Salomix mixing technology enables efficient bleach and storage tower management to ensure uniform column packing and evacuation. The top inlet sparger (TES) distributes the feedstock evenly throughout the tower filling process. The agitator located in the bottom of the tower agitator ensures that the feed pumped from the tower is of uniform consistency. Sulzer Pumps has already installed 10,000 m3 storage towers in Brazil and China. Largest R & D Center Sulzer Pumps has the world's largest research and development center dedicated to meeting the needs of the pulp and paper industry in the Karhula (FI) region. After decades of continuous and professional research, Sulzer has been able to create a raw material pumping system with longer service intervals and consume less energy. In addition, Sulzer's metallurgical technology and the company's own foundry play an important role in the development of highly corrosion-resistant and abrasion-resistant equipment. To date, Sulzer has supplied over 3,000 MC medium-strength pumping systems to customers worldwide.