Equipment description of pickling line unit

This pickling unit is a push-pull pickling unit, which is currently the most advanced shallow groove turbulent pickling technology in China. The provided process equipment and technology are proven, reliable, advanced and mature complete sets of equipment and technology that can satisfy the buyer's stable production and long-term operation. The technology has the characteristics of reasonable equipment structure, high operation efficiency, low production consumption, convenient operation, and less equipment failures.

In the designed pickling unit, the whole process of pickling steel strip from uncoiling to coiling is completed online. On the one hand, this arrangement can simplify the structure of the equipment, and on the other hand, it can make the pedestrian passage unblocked. At the same time, considering the local geological conditions, except for the uncoiler and the coiler, all the process equipment is installed in the form of an elevated steel strip, and the running plane height is 2.2m. In this way, the depth of the pit of the acid circulation system can be reduced, and the depth of the pit is about -2.5m. There is a fixed coil saddle at the entrance of the unit, and the coils stored on the coil saddle can be transported to the uncoiler drum by a hydraulically driven feeding trolley. The unit adopts double uncoilers. The expansion and contraction of the reel is driven by a hydraulic cylinder arranged at one end of the mandrel of the reel. The uncoiler frame is driven by the hydraulic cylinder and can move on the base to adjust the center position of the steel coil when it is uncoiled. In order to ensure the straightness of the steel strip when passing through the belt, a two-roller pinch five-roller straightening machine is installed at the entrance of the unit. The pickling tank is divided into 6 sections, and the lining of the pickling tank is arranged in the shape of fish scales for the convenience of wearing the belt. The tank body is of carbon steel structure, lined with neoprene rubber and granite strips, and the guide stone adopts a double-layer structure, which can avoid the maintenance and replacement of the granite lining without damaging the lining rubber layer. There are acid liquid squeezing rubber rollers and acid liquid isolation chambers between each section of the tank. The bottom of the tank is lined with granite and the lower roller surface of the squeezing rubber roller is on the same plane. The inlet and outlet of the washing tank are equipped with photoelectric sensors and displacement sensors to calculate the position of the steel belt, and automatically control the opening and closing of the upper roller of the squeeze roller. These measures can effectively ensure the normal wear of the steel strip, even the thinner steel strip can also avoid the overlapping accumulation of the steel strip in the acid tank. Each section of the acid tank is equipped with a set of acid liquid circulation heating system. The acid liquid is heated by a vertical graphite heat exchanger. The heated acid liquid is directly sprayed on the upper surface of the steel strip by the spray header. Under the action of the tank structure, the acid liquid flows rapidly in the form of turbulent flow, which greatly improves the pickling speed. The new acid is continuously and quantitatively replenished from the 6# acid circulation tank, and at the same time, through the acid circulation tank liquid level control system, it is gradually replenished to 5#, 4#, 3#, 2#, 1#, and finally discharged from the 1# tank to Waste acid collection tank. Since each section of the pickling tank is relatively isolated and circulates independently, the concentration gradient of the acid solution in each section of the acid tank can be effectively controlled. The cleaning tank is flushed with a 5-stage circulating spray. The clean water is replenished from the fifth-level flushing tank. The flushing water flows from the fifth-level to the first-level in the lower water collecting tank of the cleaning tank, and finally drains from the first-level overflow port to the first level. Flush water to collection tank or discharge to water treatment station. The entire pickling tank and cleaning tank are controlled by micro-negative pressure, and the acid mist is pumped to the acid mist washing tower through the exhaust pipes set at the inlet and outlet of each section, and then discharged to the outside of the plant after spraying and washing. The steel strip is dried by a hot air dryer, and the hot air is heated by a steam heat exchanger. The coiler adopts a floating tension coiler with a single cone head with a movable support seat. EPC controls the coiling end of the coiling. The export coil unloading adopts hydraulically driven coil unloading trolley to unload the steel coil to the export steel coil saddle, and the steel coil saddle can store 2 steel coils at the same time.

The electrical control system of the unit is composed of power distribution system, AC variable frequency motor transmission equipment, AC motor control unit, PLC operation control system, main console, and sub console. The operation control of the system is completed by the PLC programmable controller, and the operating system also includes the chain control function of the auxiliary process system of the pickling unit.