| With improvement of living standards, people’s demands for tissue paper increased a lot. The tissue paper market became more competitive today, and manufacturers face the pressures of improving the rate of first grade products, energy conservation and emission reduction. Papermaking is a kind of high technology intensitive process, requiring acurately controlling for such parameters as temperature, pressure and flowrate. However, with the development of the domestic equipment manufacturing industry, many new domestic tissue paper machines marketed out in recent years, and the gap between China and the foreign advanced tissue paper machine is decteasing. But as a result of foreign manufacturers’ technological monopoly for controlling, the domestic manufacturers don’t know much about that. Thus aiming at the production process of tissue paper machine,the primary tasks are to research on totally integrated automatic system to improve the degree of automation and control precision of domestic tissue paper machine and break the foreign technology monopoly with production safety, efficient production, saving energy and reducing consumption.The article takes the high-speed tissue machine of Sichuan Hefeng as background, funded by the project of Shaanxi science and technology coordination(foundation number: 2012KTCQ01-19), aiming at the control requirements of the systems of papermaking, from the points of production technology, control strategy, design and implementation of control plan, following works have been done in this paper.(1) The analysis of technological process and control key points.The requirements of water and basis weight,filling power is high for middle and high speed tissues machine, thus the control difficulties need to be considered during designing the subsystems. Including the difficulty of basis control for hard to apply the QCS for middle and high speed tissues machine. The energy consumption of dry-section is high, dry cylinder probably gets hydrops, affecting the safe operation of machine. On account of high speed, thin sheet and large inertia of drying cylinder, it is difficulty to ensure the continuous operation of machine for driving-section.(2)Design of control strategy for subsystems.Puts forward the control scheme in allusion to the control difficulties of subsystems. Control strategy based on fuzzy-PID control for absolute dry pulp quantity was put forward to solve the problem of the difficulty of application of QCS for middle and high speed tissue paper machine. Collaborative energy consumption control scheme between dry cylinder and holder was put forward to solve the problem of high energy consumption and hydrops of dry cylinder. Three-points driving control scheme was put forward to ensure the continuous operation of machine(3)Design and implementation of totally integrated automation system based on Siemens S7-300 PLC.Due to variety of sections and complexity of system structure, totally integrated automation system is necessary to be used. Under the concrete engineering project, Siemens STEP7+Win CC software used as development platform, build control system integrating OPC technology. Complete the communication between MATLAB and PC based OPC, and the fuzzy-PID algorithm is applied, running effect is well.In present, research of middle high-speed tissue machine totally integrate automatic system is in a state of blank basically in our country, the domestic market is monopolized by advanced foreign manufacturers. The automation system designed in this subject has applied in a production line of Sichuan Hefeng, and a good control effect is got after a long running. The steam consumption per ton of paper reduced to 2.8 tons from 3.5 tons, and the running speed increased by 12%. The degree of automation is improved and energy saving effect is obvious. This system has the advantages of easily realized, reliable operation, strong ability to scale, can be widely applied in domestic tissue paper machine production line. |
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