Digital hydraulic automatic control system for steelmaking converter gas recovery

The converter in the converting process, resulting in a large number of CO and soot. In order to prevent the gas pollution of the environment, need to use the fan pumping out a series of purification treatment. Components of qualified gas into the gas tank recovery. In the pumping process, it is necessary to prevent the mouth positive pressure overflow gas pollution of the environment, but also to avoid the negative pressure of the mouth of the inhaled too much air and reduce the quality of the gas. Therefore, it is necessary to gas pressure in the mouth for precise control, furnace gas micro pressure control. For a long time, the hydraulic servo system is widely used at home and abroad, through the control valve RD two venturi throat, micro pressure control to achieve. Hydraulic servo system must adopt the servo valve and servo cylinder, servo valve anti pollution ability is poor, prone to clogging; analog signal anti-interference ability is weak, troublesome debugging, fault; and system maintenance difficult, and even the introduction of the system there exists a lot of problems can not be normal use, the gas emissions, not only pollute the air and waste of energy.

AEMETEC through long-term attention and in-depth study found that traditional converter mouth micro pressure difference control long-term since the operation effect is poor, the key lies in the system in the presence of two difficult problems:

First, commonly used in the hydraulic servo system as the drive system and the execution unit. This system because of its poor ability to adapt, adjust links, can not ensure long-term stable use;

Second, the control strategy is generally ignored. Traditional control system using simple linear control algorithm, easily lead to system in different regions with different precision and volatility, and even cause the actuator is damaged (Shijiazhuang steel mills, for example: when the system is put into automatic control, RD valve opened quickly to a maximum and then quickly shut down, shock twice by cylinder break). Expert analysis, that delay system of this type, using the traditional linear control algorithm, is bound to cause concussion, only when the control system using fuzzy logic algorithm before they can avoid lagging behind the shock. But only the ordinary fuzzy logic algorithm, control the response of the system will become very slow, still cannot meet the converter micro differential pressure control, when the system is unable to adapt when added to the burden of instantaneous mouth pressure changes, will cause the pressure out of control. So the system but also with the intelligent control and variable structure PID regulation, to meet the system requirements for the stable and transient lag variable system request quick adjusting, the mouth is controlled by the micro differential pressure is maintained in the range from + 3-5Pa.

AEMETEC has done a lot of work on the above issues. Digital hydraulic cylinder instead of the hydraulic servo system as the execution, not only to avoid the problems of servo valve hydraulic system, makes the system greatly simplified, control way clear, simple; introduced a new type of full digital hydraulic valve control system instead of the original of the hydraulic servo system, completely avoid the run, run, drip, leak in the hydraulic servo system may bring trouble, but also to avoid the pollution and plugging. Due to the adoption of full digital drive, the new system can avoid the interference in the transmission process, especially in the harsh environment of the metallurgical field.

Digital hydraulic control system is this: first the tee valve is opened to discharge position, RD valve to open to the appropriate location, converter hood next to the appropriate location, start the exhaust fan and oxygen gun insertion start blowing. When the blowing is stable and normal, available artificial point dynamic control Rd valve and observe the mouth micro pressure, when the pressure is close to the set value, can be put into automatic. At this point, mouth micro pressure sensor values are compared with the computer set values, such as difference, computer through calculation and processing, a digital pulse signal, digital drive hydraulic control valve, fine-tuning of the RD valve, make mouth micro pressure remained near the setting value, realize the precise micro pressure control. Digital hydraulic control valve has the power, fast response, good fretting, strong anti-interference ability, long service life, and reliable work, etc. a series of advantages, not only can improve the control accuracy and greatly reduce the maintenance workload, completely solve the old gas micro pressure control of hydraulic servo system of all kinds of difficult problems, is a kind of ideal gas micro pressure control system.