High pressure cylinders made of composite materials for storage of ECG gaseous components for deep research apparatus
High pressure cylinders made of composite materials for storage of ECG gaseous components for deep research apparatus.
Y.A. Bogenov, A.S. Gadalin (St. Petersburg SMTU) O.S. Kluynin (“POISK” Ltd. St. Petersburg)
Composite cylinders on liner’s base of chromium-nickel austenitic steels and aluminum alloys with plastic winding of roving “Armos” or “Ruslan-BM-650” can stand an inner pressure of different gases to 120MPa according to thickness and type of roving’s’ winding. However, they do not work well under the outer pressure, allowing the maximum outer pressure 5-10 MPa. In terms of quantity could be considered the using of such cylinders for storage gaseous reactants by the pressure drop operation, safe the residual pressure of cylinder Ð2, compensating outer hydrostatic pressure (no less than 50 MPa). In this case there is no need for strong corps AUSA (Autonomous Uninhabited Submersible Apparatus) for accommodate of storage reagent systems using on air space. Pressure regulator and water for reaction can be placed in a strong corps of fuel cell elements system and in automation system (pic. 3.3.12), which size can be degreasing in compare with 1st and 2nd variants. On the structured scheme is marked maximum degrease of inner pressure of technologies which are developed. It is the real opportunity to increase the pressure up 120 MPa which accepts for the further calculations.
Picture 3.3.12 the structured scheme of placement ECG systems in AUSA at gas-compressor storage of reagents in composite cylinders in seawater.
The gas volume Vã at max pressure Ð1 which need for mass flow rate Ìã can be determined from the equation
|Vã· ρ(Ð1) – Vã ·ρ(Ð2) = Ìã,|
where ρ(Ð1) è ρ(Ð2) - the real gas density at initial pressure Ð1 and at final pressure Ð2, defined by the equation of van der Waals. It shows
|Vã = Ìã /[ρ(Ð1) – ρ(Ð2)]|
that the hydrogen cylinders are critical in there volume. For Ð1 = 120MPa ρÍ2 = 0,043kg/dm3. For Ð2 =50 MPa ρÍ2 = 0,028 kg/dm3. In setting with power Ðáòý = 1800W for Ìã = 10 kg require the hydrogen capacity Vñõâ Í2 = 670 dm3. In setting with power Ðáòý = 3200W the hydrogen storage capacity will be Vñõâ Í2 = 1670 dm3. Research and Production Association “POISK” Ltd. (St. Petersburg) produces the composite cylinders BD-40 for hydrogen transportation under the pressure 40 MPa with capacity from 1000 till 2500 l (pic. 3.3.13 and 3.3.14) with assurance factor êð = 2.6 .
A big mass and dimensions of cylinder which minimize capacity 1000 l: weight Ìá= 900; length Lá =1900 mm; outside diameter Dáí = 1134 mm do not allow to place it in a limited displacement AUSA. It takes moreover the increase of wall thickness on the pressure 120 MPa.
Pic. 3.3.14 Metal-plastic cylinder BD-40 for nitrogen’s storage and transportation with capacity 2500 l.
|Cylinders liner BD-40 with diagnostic elements||The winding of pressure cylinders shell BD-40|
To realize the required volume nitrogen storage, parameters of strength and mass of cylinders in AUSA, calculations are made for cylinders with lower capacity based on steel liners with diameter 290 mm. The safety factor is reduced to êð = 2,4. The thickness of the reinforced wall is 54 mm. The outside diameter of cylinder is 400 mm. The main parameters of cylinders for accommodation of 670 l hydrogen at pressure 120 MPa are given 3.3.11.
Table 3.3.11 Parameter of metal-plastic cylinders at calculated pressure Ðð = 288 MPa and mass of hydrogen consumed ÌÍ2 = 10 kg
|Cylinders||Weight of liner, kg||Weight of plastic, kg||Weight of cylinder, kg||Length of cylinder, mm||Water displacement, dm3||Weight of all cylinders, kg||Water displacement of all cylinders|
|8 to 85 dm3||10||108||118||1365||150||944||1200|
|6 to 114 dm3||13||144||157||1810||200||942||1200|
|4 to 172 dm3||20||215||215||2700||308||860||1232|
Serial produced petal-plastic (composite) cylinders with high pressure
Cylinders for hydrogen and oxygen with capacity from 80 till 160 dm3 at working pressure 44 MPa.
Composite cylinders for hydrogen and oxygen with capacity from 20 till 80 l, operating pressure 41 MPa
Metal-plastic cylinder BMA-40 for nitrogen, oxygen and helium capacity from 100 l, operating pressure 40 MPa.