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

Compressed Hydrogen Storage Tank Price Calculation

Hydrogen pressure vessel minimum plate area : 59.460,226 mm2

Based on the marketplace above the surface area of 1 plate is 200.000 mm2. The minimum thickness is 1,4 mm so 2 mm plate is the safe option for this pressure vessel and 2 mm plate is common plate thickness in indonesia. so we only need to purchase 1 piece of plate. The price is 151.900 rupiah.

We need to purchase mild steel rod for the input and output port, the price above is per cm of rod length, we need 5 cm for the length of rod. So the total price is 4.000 rupiah.

We need to process the rod raw material using lathe machine, based on the price above processing 2 pcs of raw material will cost 20.000 rupiah.

We also need to cut and roll the plate raw material to the desire shape of the pressure vessel. The plate will need 7 times of cutting process and 3 times rolling process. So the total price of cutting and rolling process is 100.000 rupiah.

After cutting and rolling, we need to weld the processed plate together. The total weld length needed is 1.351,804 mm. The price above is per meter of weld length, so the welding process price is 135.180 rupiah.

The final process is painting, we could do the painting by ourselves with aerosol paint. The aerosol paint price is 30.000 rupiah.

The total price of manufacturing the hydrogen pressure vessel is 151.900 + 4.000 + 20.000 + 100.000 + 135.180 + 30.000 = 441.080 rupiah. The manufacturing price is still under the specified budget 500.000 rupiah.

Youtube Link for Compressed Hydrogen Storage Tank Presentation Video

Youtube Video Pemahaman Numerical Methods & Pengaplikasiannya dalam Perancangan Bejana Tekan Hidrogen.