Aldebaran Fernanda Octavian

Introduction

Hello! my name is Alde, I'm in mechanical engineering major continuing my study from diploma 3 to bachelor's degree throughout University of Indonesia parallel program.

Life motto? Everybody has their own start and finish line, start creating yours.

Full name : Aldebaran Fernanda Octavian

NPM : 2206100180

Compressed Hydrogen Storage Tank Design

Customer requirement list :

1. Storage tank volume is approximately 1 liter.

2. Hydrogen is compressed to 8 bar of gauge pressure.

3. Normal operating condition (room temperature and humidity).

4. Output and input port for hydrogen filling and exerting.

5. Add pressure regulator for output port.

6. Maximum budget is 500.000 rupiah.

Determining hydrogen phase :

According to hydrogen phase diagram above, hydrogen at 8 bar of gauge pressure and 25 degree Celsius, is in gaseous phase.

Determining tank size :

First step is to determine the tank inner diameter : 100 mm

According to the equation above, the inner height of the tank is h = 1.000.000 / 3,14 x 50 x 50 = 127,32 mm

Note : the height will decrease because the ellipsoidal head will add extra volume.

Tank design calculation :

All of the design calculation are based on ASME Section VIII Pressure Vessel standardization.

1. Material allowable stress value :

Material : ASTM A36 sheet metal ; Yield Strength (Sy) : 36 Ksi

Allowable stress value = 2/3 x Sy = 24 Ksi

2. Wall and head minimum thickness :

Thickness formula for circumferential stress direction :

Thickness formula for longitudinal stress direction :

E = 0,60 (Single-welded butt joint without use of backing strip)

P = 8 bar = 116 Psi

R = 50 mm = 1,97 inch

S = 24000 Psi

Corrosion allowance = 1 mm = 0,039 inch

t = 116x(1,97+0,039) / (24000x0,6)-(0,6x116) = 0,0162 + corrosion allowance = 0,5526 inch

t = 1,4 mm (Circumferential) ; t = 1,2 mm (Longitudinal)

So, the minimum thickness of the sheet metal is 1,4 mm

Head Design :

Computer Aided Stress Analysis :

1. Von Mises Stress Analysis

2. Safety Factor

The design could be improved by increasing the minimum safety factor value to 3 or 4, by increasing the wall and head thickness of the tank.

Final Product Specification :

Tank Outer Diameter : 102,8 mm

Tank only length : 147,8 mm

Total length : 156,4 mm

Wall and head thickness : 1,4 mm

Tank Capacity : 1,005 liter

Finishing : Painted

Compressed Hydrogen Storage Tank Minimum Thickness in Numerical Method with Python Code

1. Aldebaran Fernanda Octavian_2206100180

1. ASTM A36 material properties

yield_strength = 250 # MPa safety_factor = 1 # Safety factor

1. Function to calculate the minimum required steel thickness

def calculate_thickness(pressure):

   # Convert pressure from bar to MPa
   pressure_mpa = pressure * 0.1

   # Calculate the minimum required thickness using the formula from ASME BPVC
   thickness = (pressure_mpa * safety_factor) / (2 * yield_strength) * 1000  # Convert to millimeters

   # Return the thickness in millimeters
   return thickness

1. Test case with 8 bar working pressure

working_pressure = 8 # bar optimum_thickness = calculate_thickness(working_pressure)

print(f"The optimum steel thickness for a pressure vessel with {working_pressure} bar of working pressure is {optimum_thickness:.2f} mm.")