Andritz is one of the leading suppliers of international pulp and paper equipment. In recent years, through the merger and reorganization with Konewood, Sulzer and other companies, the scope of supply has included log yards and wood preparation, wood chip thermo-mechanical pulp (TMP, CTMP, APMP), high-efficiency filtration and dewatering equipment, and new pulping machines. Wet, high-speed toilet paper machine and so on. The company attaches great importance to the development of energy-saving technologies and equipment. The latest achievements in pulp production are described below:
1. TMP disc refiner improvement The newly developed RTS (Residence time, temperature and speed) technology is based on the original TMP improvement, mainly to improve the refining speed. Taking the TWIN66 new disc mill as an example, its rotation speed has increased to 2300r/min (the original TWIN60 disc rotation speed is 1500r/min, which can save about 20% of the unit's output power consumption, and the various properties of the slurry, such as The fiber uniformity, strength, optical properties, and paper surface properties are all superior to those of low-speed milled TMP: in order to meet the good separation of fibers at the beginning of the high-speed, high-strength mill process, the test confirms that the wood chips must be well preheated. The temperature reaches above the glass transition point (Tg) of the lignin, of course, due to the increase of the refining speed, the corresponding equipment manufacturing accuracy, such as balance, material properties, control, and operation level, must be accordingly followed.
RTS technology has been successfully applied to production practices, including the transformation of existing TMP production lines and the construction of new TMP production lines, such as the new TMP production line in Canada's Stora plant, Nissan 770t (dry), which was put into production in 1997. The TMP production line is a three-stage refining process, in which the TWIN66 type is used for the first and second stage disk mills and the SBl50 type single disk mill is used in the third stage, which has received a significant energy saving effect.
2. High-efficiency filtration and dewatering equipment Andhtz can provide a variety of filtration and dewatering equipment, such as multi-disc filter, screw-pushing machine, double-web squeezer and so on. In particular, it is known for its high-performance double-wire presses. It is widely used not only as a peroxide for mechanical pulps and TCF pulps, as well as high-concentration bleaching of ozone and sludge dewatering, but also has become the world's most advanced energy-saving paddle trigger. Wet equipment. The latest such slurry triggers have been put into operation in some new large pulp mills in Southeast Asia. Compared with the traditional long-wire transfer machine wet end, the energy saving can be 28 degrees per ton, and for the l000t per day plasma trigger, the temperature load can be reduced by 1 000 kW: the double-grinding machine and the high-strength pressed pulp machine are wet. The dryness of the propeller can reach 50%-56%, which is 3%-9% higher than that of the traditional long-winding wet machine, so the steam consumption in the dryer can save 10%-30%. Whether the reformation of domestically-produced existing paddle triggers and the design of the new-generation paddle engine should be considered to replace vacuum dewatering with dewatering, especially for straw dewatering, to achieve energy-saving purposes.
3. High-efficiency Low-shear Force Mixer The other companies in the world produce mixers for medium-to-dense technology. They usually achieve high mixing force and high energy consumption. The medium and high-consistency mixers developed by ANDRITZ use low shear forces, which can reduce power consumption while ensuring the mixing effect. The structure of the high-consistency mixer is characterized by that the pulp enters the mixer firstly through a horizontal belt screw conveyor, which can both loosen the slurry and ensure even feeding. Chemicals pass through the shaft of the screw conveyor and are sprayed into the slurry. The pulp and chemicals are initially mixed in the taper screw, and then enter between the moving plate and the fixed plate with sharp thorns. The shredding of the high consistency (25%-30%) slurry and the final uniform mixing with the chemicals were completed. This kind of high-concentration mixer has been installed in 100 sets around the world, and the power consumption per ton of pulp is only 5-10 degrees. For a production line with a daily production capacity of 5 DDt, only a load of 100-200 kW is required. This high-concentrator cannot be energy-efficient and is ideally suited for the mixing of heat-sensitive bleaching chemicals such as ozone and peroxide, and also prevents paper fiber damage and excessive distortion due to high shear forces.
The TWIN SF Mixer type is suitable for the mixing of gaseous bleaching chemicals. Its structure does not allow the slurry to enter the very narrow gaps, and the high shear force is used to mix it with the chemicals. With higher power, it is a kind of pipe-type hybrid equipment. The mixer is flanged to the slurry tube like a valve. The two oval-ring rotors in the body create high turbulence in the flow through the pipe and break up the bubbles for good mixing. This mid-concentrator mixer is used for a 50-kilogram electric load in a section of the Nissan 1000t slurry, while other high-shear mixers are generally 100-150 kW.