Design Calculation and Thickness verification for product load, wind load & seismic load of Tank 612 as per API 653 of Mahul Refinery HPCL, for TATA projects Limited

TATA Projects Limited has entrusted iFluids Engineering to check the Tank Design Calculation and minimum thickness verification considering Product load, Wind and Seismic Loads as per API 653/650 standard for HPCL Mahul Refinery.

The main objective is to check the tanks stability and adequacy as per API 653/650 standard. The software checks the arrived shell course thickness, to verify if it is within the allowable limit with the stable condition and risk of overturning.

Codes and Standards:

  1. API 650                   –         Welded Tanks for Oil Storage
  2. API 653                   –         Tank Inspection, Repair, Alteration, and Reconstruction
  3. API 620                   –         Design and Construction of Large, Welded, Low-Pressure Storage Tanks
  4. API 579                   –         Fitness for Service  

Tank Design Calculation:

In the software the input details were given based on the GA drawing, thickness measurement report for calculation of the product load, wind load, seismic load for the shell courses. The Tank details will be varying in Floating roof, product stored, capacity, dimensions.

The Calculations are following below:

  1. Calculation of shell course thickness by using one foot method by considering the three cases:
  2. Design Case
  3. Test Case
  4. Required Case
  5. Seismic Evaluation calculations as per the following:
  6. Seismic Analysis
  7. Seismic Hoop combined Force/Stress
  8. Seismic Hoop Allowable
  9. Wind load calculations as per the following:
  10. Wind Velocity Factor
  11. Vertical projected wind area of tank
  12. Velocity pressure
  13. Wind moment on shell
  14. Vertical projected wind area of Cone roof
  15. Area Exposed to Wind
  16. Wind moment at the base including the cone roof
  17. Wind shear force acting on the tank
  18. Moment about shell-to-bottom joint
  19. Resisting Weight of Fluid
  20. Moment from Fluid Weight
  21. Moment from Design Internal Pressure
  22. Design Pressure

As per API 653/650, tank design calculation results along with recommendations were provided for the arrived thickness of the shell courses. The product load, wind load and seismic load was verified to be within the allowable limit with the stable condition and risk of overturning or not, which were reviewed by the HPCL Mahul Refinery.