Application of Hydraulic Jacking Inversion Method in Large Storage Tank

With the continuous development of the petrochemical industry, the demand for storage tanks is increasing. For many years, the manufacturing of storage tanks mainly adopts the central column method, air blowing method and water floating method for storage tank construction. Due to the gradual development of large-scale storage tanks, some construction technologies can not meet the construction requirements, and it has become a trend to use hydraulic lifting inversion method to replace other construction methods in the construction of large-scale storage tanks. The technical requirements of hydraulic lifting inversion method are not difficult, safe and reliable, the construction method uses less materials, the installation speed is fast, and the various construction parameters of the storage tank are easy to adjust and control, which can avoid the risk of roof falling and blowing accident caused by the use of air blowing method. It is currently a relatively ideal new method for the construction of storage tanks. This paper introduces the construction method and construction principle.

Key words: Hydraulic jacking system; Construction application; Large storage tank

Construction principle

The upper and lower unidirectional clamping head is installed on the hydraulic jacking frame distributed on the inside of the storage tank. The upper clamping head is equipped with a hydraulic cylinder, and the power comes from the central console. The high-pressure oil is sent to the bidirectional cylinder (upper clamping head) through the hose, and the reciprocating action of the cylinder is realized through the reversing valve. The piston rod is hollow, and there is a steel jacking rod in the middle, which can complete the stepping work of the jacking rod when the cylinder is reciprocating. The jacking rod drives the bracket on the jacking frame, and the bracket moves along the track of the bracket, and stops when the expansion ring temporarily fixed with the lower part of the tank wall is lifted to the lower part of the second circle of wall panel. After the installation of the second circle of wall panel and the welding of the first circle of wall panel is completed, the bracket is lowered, the first circle of wall panel is supported by the second circle of wall panel, and the second circle of wall panel is expanded and supported by the second circle of wall panel. Then uprating, fixing so reciprocating, so that the tank lifting, to achieve the flip method of construction technology requirements

Construction process

Tank prefabrication and foundation acceptance → Tank bottom assembly welding → Hydraulic jacking device and expansion ring installation for the 1st round wall panel and wrapping Angle steel assembly welding → Welding for the 2nd round wall panel coaming and outer longitudinal seam → Welding for the 1st round tank wall assembly → Welding for the 1st and 2nd round wall panel 1 Drop the expansion ring and reinstall the expansion ring → Welding for the top of the tank and labor protection facilities → Welding for the 3rd round wall panel → Repeat the above steps until the formation Weld the last round of wall panel → remove the jacking device → weld the large corner seam and shrink seam at the bottom of the tank → overall test of the tank → anti-corrosion and heat preservation → completion.

Process characteristics

The construction of large storage tanks by hydraulic jacking upside-down method has the following characteristics :

(1) less high-altitude operation, good safety and basically ground operation;

(2) Less space can be occupied in a narrow area of construction;

(3) In addition to the expansion ring can be reused in different specifications of the storage tank :(4) the use of hydraulic mechanism, small volume, uniform lifting;

(5) Change a single control to a central control:

(6) Continuous jacking is changed to step jacking, and the jacking height is controllable to prevent uneven jacking;

(7) The construction quality is easy to guarantee. It is mainly reflected in: the roundness of the tank wall is good, and it is very easy to locate the ring seam welding of the wall plate because of the expansion ring. The girth welding deformation is small and the flatness is good. Under the action of expansion ring, the girth welding stiffness is greatly increased, which effectively inhibits the shrinkage deformation. Tank verticality is easy to guarantee, as the lifting height can be adjusted individually for each jacking frame:

(8) Strong adaptability. This method is suitable for the construction of fixed roof and floating roof tanks above 1000m3. When used for the construction of floating roof tanks without roofs, the roof of the tank should be reinforced to prevent construction deformation:

(9) Low construction cost and good economic benefits.

Conclusion

Hydraulic jacking upside-down method is an ideal new method for the manufacture and installation of storage tanks. It is suitable for the manufacture and installation of more than 1000 cubic meters of vaulted tanks, inner floating tanks and no roof tanks, especially for the manufacture and installation of more than 20,000 cubic meters of vaulted tanks, inner floating tanks and no roof tanks, which has the advantages that can not be replaced by other construction methods, and has broad development prospects. It is worth promoting and applying.