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Glass melting furnaces are typical large-lag, nonlinear uncertain objects, which cannot be described by mathematical models. Therefore, conventional control methods are often not well controlled, and can be realized by using a flying system. entireFloat glassAutomated systems can be decentralized and centralized.
The characteristics of the system are as follows:
(1) The operation mode adopts the combination of dispersion and concentration, that is, the raw materials, ingredients, tin kiln, annealing kiln, packaging, and tempering can all be controlled locally, but can also be concentrated in the central control room for control (by lock) Select the switch to select), which is easy to operate, control and reduce the number of personnel. Its detection and control use BCS and connect to the network, enter the process level and its display device, the data can be shared, and the display screens of each display can be called each other.
(2) Unified consideration, but can be implemented step by step, for example, the key ingredients and the melting furnace system can be applied first to receive a large effect.
(3) The structure of the three-level automation system, that is, the basic automation of the test drive stage L1 including the instrument actuator, various electrical equipment, the motor control center, the speed control device, the industrial TV, and the equipment control level L2 composed of the BCS Process automation of monitoring level L3.
(4) Integration of management and control. The system can include certain management functions such as quality analysis, statistics, and planning, as well as in the director's office and dispatch room.
(6) The industrial TV network is integrated with the EICC four power (transmission, instrumentation, computer, communication), and constitutes a typical new system with multimedia technology. CCD Industrial TV will enter the EICC system through the BCS.
(7) Using a large-capacity (hard disk 1. 7G, memory 16M or more) industrial PC instead of the traditional process computer, not only saves investment and increases flexibility.
(8) Use IE integrated equipment. That is, the whole PLC system not only has a lower cost than the DCS, but also integrates the electric equipment to reduce the spare parts.
(9) Use artificial intelligence technology (fuzzy control or expert system) to control the operation of key equipment melting furnaces to achieve energy saving and extend the life of the kiln, so that inexperienced operators can reach the level of skilled operators. Use neuron network technology to predict the quality of the glass in order to correct the ingredients and take other measures in a timely manner. After changing the process parameters, predict the production technical indicators to make decisions and strengthen production. In addition, the traditional control is PID mode, but it is difficult to adapt to many disturbances and load changes in practice. Especially with the change of production, the valve is not flexible, the valve diameter is too large, and the control quality cannot be satisfied. When it appears, it can not be used, it becomes manual control, and it is solved by fuzzy control at home and abroad. It is fuzzified and optimized according to manual operation rules, which not only makes it possible to re-automate without replacing any equipment (because it is generally It is difficult to replace the regulating valve, which is not only expensive, but also has to be discontinued and installed, and even the pipe is made to shrink the pipe to meet the valve diameter requirements, which is difficult to achieve). Moreover, the adjustment quality is better than the PID. For example, the adjustment time, the attenuation, the number of fluctuations, and the control quality are superior to the interference. It is especially suitable for adjusting the temperature of the hot gas gate to control the kiln because of the hot gas gate plate. There is tar and is not flexible. In addition, a neural network can be used to make the combustion, that is, the air-fuel ratio and the flame temperature, solve the problem that it is difficult to achieve the air-fuel ratio control because the hot gas flow cannot be measured.
(10) Use new solutions and new advanced control methods. (Some methods belong to the company's unique technology, not introduced here.) The cost-oriented optimization mathematical model is used to calculate the ingredients to reduce costs and increase market competitiveness.
A: Process automation
Mainly as a monitoring of the entire production process, its main functions are:
(1) Data collection. The time series data of the process parameters including the whole process such as pulverization, batching, melting, forming, cutting and packing, and the manually input parameters are collected.
(2) Setting of production process parameters. For example, tempered glass production needs to set the tempering parameters (pressure, distance between glass and tuyere, power, etc.), motion parameters (oscillation time, speed, acceleration, etc.), adjustment parameters (heating temperature and time of each section) Etc.), it is selected according to the thickness and specifications of the glass. The tempered glass production line introduced by a factory in Switzerland from SATTIN has 31 specifications, that is, 31 sets. These are stored in the upper computer and are called out when used.(3) Model calculation. Examples include batching calculation models, batching optimization (very low cost) models, and so on.
(4) Advanced control and artificial intelligence applications. Including furnace temperature fuzzy control, furnace pressure fuzzy control, batching fuzzy control, etc., it solves the lag of the conventional PID control, the valve diameter is too large, the inflexible, non-linear object and system oscillation, and the poor quality adjustment. Another use of artificial intelligence is the fuel-to-air ratio self-optimization to solve the problem of high flame temperature ratio, which uses a neural network approach.
(5) Quality prediction. It adopts statistical method modeling or neural network method. It can predict the quality of flat glass by using the ingredients and the process parameters used. It is only necessary to know whether the ingredients are correct and not timely after the finished products are out. In addition, it is necessary to change Operating process parameters, strengthening production, can also be used to predict for decision making.
(6) Data display. Time series data including process parameters, transient data, process flow chart and key dynamic data, alarm status data, historical data query, various reports, special display, model display, setting data, stored process parameters, curves, quality Standards and technical procedures, etc.
(7) Data recording. Including newspapers, daily newspapers, monthly reports, alarm reports, etc. Print, hard copy of data and graphics.
(8) Data communication. This includes communicating with the plant management computer, the lower computer, the plant manager, and the dispatch room computer or terminal.
(9) Other management functions. Such as equipment diagnosis, planning, long-distance production process in the director's office and dispatching room.
B. Basic automation
The following is a description of the melting furnace. The basic automation functions of the melting furnace include (1) data acquisition: kiln temperature, kiln pressure, flue suction, glass level, gas or heavy oil and air pressure; (2) kiln pressure fuzzy automatic control; (3) temperature blur of each section Expert system control; (4) use of neural network to achieve air-fuel ratio optimization control; (5) automatic flame reversal; (6) automatic control of glass level; (7) temperature level, gas or heavy oil and air pressure alarm, etc. .
Melting furnace control points: AI: 13 points AO: 7 points DI: 58 points DO: 16 points
Its BCS structure diagram is as follows
According to the control requirements, three artificial intelligence development software platforms, namely fuzzy control, neural network and expert system, are selected.
Then, referring to the flying system price list, the engineering cost of the melting furnace intelligent automation system can be calculated.
C. Benefits of using the flying system enterprise
The flat glass production process is automated, which can save energy by 15%-20%, increase production and yield by at least 5%, and save manpower and reduce the number of people to obtain significant economic benefits. The following is an example of Beijing Flat Glass Group Co., Ltd.
(1) After the company is put into use, due to the improvement of glass quality, cost reduction and furnace life, the annual profit can be increased by 15.82 million yuan.
(2) Improve the quality of the glass, the company's annual new profit of 4 million yuan
Through the correction of moisture and weight in the ingredients, quality prediction and temperature control of the three thermal equipments, the glass yield is increased by 30%, and the annual production of 51,000 weight boxes of glass can be achieved, with an annual profit of about 3 million yuan. And the quality rate will be increased by 5%, from the original 5% to 10%, that is, it can produce 85,000 weight boxes of high-quality glass, creating an economic benefit of 1 million yuan.
(3) Reduce product costs, the company's new annual profit of 4.82 million yuan.
1 Through the optimization of glass ingredients, it can save 2% of the cost of purchasing raw materials. For Beijing Flat Glass Group, the annual cost of purchasing raw materials is 27.6 million yuan, then it can save 560,000 yuan.
2 Reduce the cost by 4.26 million yuan through energy saving.
a. Reduce fuel consumption by 15%, save 8100 tons of coal, and save 2.26 million yuan. The specific ways are:
·Moisture correction makes the melting furnace ingredients easy to melt, reducing fuel consumption by 5%
· Air-fuel ratio optimization, reducing fuel consumption by 10%
b, reduce tin consumption
From the original 7g / kg glass liquid, reduced to 3-4g / kg glass liquid, saving 1 ton of tin per year, worth 200,000 yuan.
c, saving electricity
The use of intelligent electric heating system and fuzzy temperature control and frequency conversion device in the tin bath and annealing kiln can save 15% of electricity consumption, save 5.6 million kwh per year, and reduce electricity costs by 2.8 million yuan.
(4) Improve the life of the kiln, with an average annual saving of 7 million yuan.
From the original 4 years to 5-6 years, with an increase in life expectancy of one year, the annual production of 1.7 million weight boxes of glass. Can save more than 7 million yuan for the company.(5) Reduce the generation of black smoke and protect the environment. Basically, no black smoke emerged.
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