Written by: Andre Santos

1. Transportation System Hydrogen
2. Hydrogen Storage System OFFSHORE STORAGE SYSTEM REPORTOFFSHORE STORAGE SYSTEM REPORTPtt Storage System Hydrogen pptx

This describe a storage system where the hydrogen is kept inside the tank

1.1 Offshore storage system.

1.1 Offshore storage system.

Produced hydrogen gas can be compressed at 700 bars by an ionic compressor to reduce storage volume. However, this pressure of gas can be increased gradually in five steps where the energy is likely to continue losing and close to zero. Therefore, this process requires a minimal maintenance requirement where the compressors seems to be suitable for offshore operation. First, this quantity which is being produced about 377400 kg is likely to related to the density of hydrogen at elevated pressure which can be estimated by using thermodynamics principles. This theory is associated with van der Waals equation  , where, P, V and T are represented  the pressure, volume and temperature of the gas respectively; moreover, n represents the number of moles of gas present, and R is the universal gas constant (8.314 N. m/mol. K). Furthermore, the equation which is likely to be used two constants (α and b) are likely to be

determined by experiment process for hydrogen where the values of 0.0244 Pa. (m3 ) 2.mole -2 and 0.0266*10-3 m3.mole -1 for α and b respectively .However , the compressibility factor is likely to be introduced  as variable, Z which  represents the deviation of a real gas from the ideal gas approach by a given equation : PV=nZRT where the behavior of hydrogen can be deviated   such a significant way from the ideal gas model. However, the quantity of Hydrogen in storage system can be estimated by its compressed volume which is 9430.05 NM3 normal volume cubic meter. Moreover, it can be calculated 39.76 kg/m3 *9430.05 m3 as where the value 39.76 kg/m3 is the density of hydrogen by compressibility z factor 1.4 at 70 Mpa or 700 bar pressure. Therefore, the result is likely to be 374938. 788 kg which nearly compared to 374440 kg the produced quantity of Hydrogen.

Fig 1 .  Compressibility factors of hydrogen at High pressure.

Pressure (MPa)	0.1013	5	10	20	30	35	40	50	70	100
Z	1	1.032	1.065	1.132	1.201	1.236	1.272	1.344	1.489	1.702

Table 1 – Hydrogen compressibility factors (Z) at 20°C Pressure (MPa)

HHV (MJ/M3	LHV(MJ/M3)	Normal conditions
12.75	10.8	At 15
12.71	10.8	At normal conditions
11.7	9.9	At 25
5.312E+7	4.491E+7	374400 Kilograms

                    

                    Table 2 – Volumetric energy density of hydrogen.

H2(g) + ½O2(g) ↔ H2O(g) ∆Η298.15 Κ = −241.826 kJ/mole this equation has been considered applicable when hydrogen is likely to be produced as vapor or gas.  In , addition , we considered at normal 20 which is nearly associated  with conversion factor LVH lower Heating value 119.96 and High Heating value which is 141.88.Therefore, LVH is likely to be considered because of gaseous state where 119.96 *37400 converted to Mj  4.491E+7 MJ.

1.2 Storage System Hydrogen Technology.

The group has been considered the high pressure of hydrogen at gaseous state and the offshore environment related to project involved including the similarities with oil and gas industry. Furthermore, hydrogen gas has been considered by its rapidly refueling at this state. However, three main point were considered to design a capable tank to store hydrogen compressed gas .

• Material
• Thickness
• Capacity

1.3 Design Pressure vessel for storage System

Code ASME Design Material SA 516 Grade 70  Code design

Grade	Tensile Strength Ksi [MPa]
55	55-75
60	60-80
65	65-85
70	70-90

Tab 3 Mechanical properties of A516 shows that at grade 70 the material is likely to have the durability.

Month	Carbon Steel Price	Carbon Steel Index	Stainless steel 304 Price	Stainless Steel 304 INDEX
Oct-19	621	155.6	2622	139.7
Sep-19	645	161.7	2547	135.7
Aug-19	657	165.3	2406	128.2
Jul-19	660	167.4	2381	128.2

Tab .4 this shows the low cost of carbon comparing to other material .

	Carbon content	Manganese content	Ductility
High carbon	0.6-1.25 wt. %	0.3-0.9 wt. %	Low
Medium carbon	0.25-0.60 wt.%	0.60-1.65 wt.%	low
Low carbon	0.25 wt. %	NA cold work	High ductility

Tab. 5

Although , low carbon has been described as soft and low strength , they have the highest ductility which make them available for welding and low cost .However, an exception of low alloy steel   which is likely considered low carbon has a high strength and contain others metals such as copper, vanadium , nickel and molybdenum. According to Matmatch, once they are combined their content

Type	AISI/ASTM name	Carbon content (wt.%)	Tensile strength (MPa)	Yield strength (MPa)	Ductility (% elongation in 50 mm)	Applications
Low	1010	0.10	325	180	28	Automobile panels, nails, wire
Low	1020	0.20	380	205	25	Pipes, structural steel, sheet steel
Low	A36	0.29	400	220	23	Structural
Low	A516 grade A	0.31	485	260	21	Low-temperature pressure vessels
Medium	1030	0.27 – 0.34	460	325	12	Machinery parts, gears, shifts, axles, bolts
Medium	1040	0.37 – 0.44	620	415	25	Crankshafts, couplings, cold headed parts.
High	1080	0.75 –0.88	924	440	12	Music wire
High	1095	0.90 – 1.04	665	380	10	Springs, cutting tools

is likely to be 10 wt. %. This means that it retains ductility and high strength and it can be claimed

that they are resistant to corrosion easily. However, at temperatures below 120°C carbon steel can be used up to high pressures. At elevated temperatures and significant pressures hydrogen will penetrate carbon steel and react with the carbon to form methane. This results in a loss of ductility and cracking or blistering of the steel. For high temperature applications steel alloys containing molybdenum and steel are satisfactory. However, low carbon has been chosen to be the level of type of material of the tank formable and machinable. In addition, ASTM is considered structurally appropriate steel for pressure vessel. Therefore, this toughness is likely to associated with manufacturing vessels for pressurised gas (LPG, butane and propane tanks), parts for steam boilers, pressure piping and compressors etc.

Grade	Maximum C % for thickness t (mm)	Mn % for thickness t (mm)	Si %	P % max	S % max
	6-12.5mm	12.5-25mm	25-50mm	>50mm	≤12.5mm	>12.5mm
A516 Grade 55	0.18	0.2	0.22	0.25	0.55-0.98	0.60-1.30	0.13-0.45	0.035	0.035
A516 Grade 60	0.21	0.23	0.23	0.25	0.6-0.9	0.80-1.20	0.13-0.45	0.035	0.035
A516 Grade 65	0.24	0.26	0.26	0.28	0.85-1.20	0.85-1.20	0.13-0.45	0.035	0.035
A516 Grade 70	0.27	0.28	0.28	0.3	0.85-1.20	0.85-1.20	0.13-0.45	0.035	0.035

Tab 7 shows the ASTM A516 material Chemical Composition.

Grade	Tensile strength	Minimum yield strength	Minimum elongation (%) gauge length
	(MPa)	(MPa)	50mm	200mm
A516 Grade 55	380-515	205	27	23
A516 Grade 60	415 – 550	220	25	21
A516 Grade 65	450 – 585	240	23	19
A516 Grade 70	485 – 620	260	21	17

Tab 8 SA516 material Mechanical Property: shows that A516 is considerably for high resistance, good weldability   and suitable for boiler fabrication including low temperature.

Therefore, the default allowable stress is likely to be 15150 psia, according to the ASME code allowable for carbon steel.

1.4 Geometry and layout (PRESSURE VESSEL)

Geometry of pressure has been associated with different factors such as maximum allowance, stress, design pressure, corrosion, density of material, price and thickness.  The group has decided to use 700 bar as the design pressure which related to the type of the tank is associated with type IV.

• The following 4 types of high-pressure vessels are classified
• Type I: pressure vessel made of metal
• Type II: pressure vessel made of a thick metallic liner hoop wrapped with a fiber-resin composite.
• Type III: pressure vessel made of a metallic liner fully wrapped with a fiber-resin composite.
• Type IV: pressure vessel made of polymeric liner fully wrapped with a fiber-resin composite. The port is metallic and integrated in the structure (boss).

Therefore, the tank is considered geometrically cylinder due to less cost and easy circulation of the hydrogen inside the tank comparing to Spherical vessel.

Pressure vessel cylindrical shell.

This figure demonstrates the geometry of pressure vessel in storage system.

where {\displaystyle \sigma _{\theta }} is representing hoop stress, or stress in the circumferential direction =     , {\displaystyle \sigma _{long}} is stress represented in the longitudinal direction σlong = p(r-0.4t)/2tE, p is internal gauge pressure, r is the inner radius of the sphere, and t is thickness of the sphere wall. However, it is likely to be into consideration the winding angle of 54.7-degree carbon fibers vessels which may give twice the strength of both longitudinal and circumferential stress.

2.1 Calculation of the pressure vessel.

Allowable stress can be calculated by yield strength 260 Mpa of the material calculated to the safety factor of material  3 .5 as the safety factor is likely to be described as how much is strong the intended loads .Therefore , Allowable stress =  this is likely to define the lifecycle of the tank .Thickness min required t =    where E is the joint efficiency which is related to the thickness , weight of the tank , P is likely to be the external pressure or design 700 bar .

Ratio 1:4	M(meter)	DESIGN PRESSURE	10152.6	bar
DIAMETER	1	ALLOWABLE STRESS (s)	23300	Psi
Radius	0.5	External radius	19.68	inch
LENTGH	4	Max Allowance Pressure	558.49	psi
Min. THICKNESS	0.09	Wall thickness	1.7	inch
Corrosion Allowance	0.125

2.2 SIZING HORIZONTAL VESSEL

Tab 9

Lc = length longitudinal cross, Lr – length right, LI- length left L = Ll+Lc+Lr =

O.D – outside diameter, ID- inside diameter, OD=ID+2*t/12 = 1.2 m

     total cross area is likely to be where

vapor space as a cross-sectional L = Ll+Lc+Lr = 4.4 m

t =      ; t =    =  3.9 inch converted to meter is 0.09 M. In addition, has been assumed 23300 psi as allowable stress in division 3 tank type 4 according to design code ASME.

However, P = , seems to be considered max allowance pressure which is likely to be defined as workable pressure. This pressure is used as a relief device to maintain the tank safe when it is shutdown or alarm. Furthermore, wall thickness t = + CA = 1.7 inch  which is equivalent 0.04318 Meter ; where CA represent the corrosion allowance which is likely to be considered a crucial point at tank process where 0.125 has been chosen as a value of corrosion allowance to prevent corrosion and failure. Moreover, R is considered the internal diameter.

2.3 LOAD OF THE TANK

A(leftend)=(*(2*(OD/2) ^2+Ll^2/e*LN((1+e) /(1-e))))/2	1.46	m
A(cylinder) = *OD*Lc                                                                          15.119	m
A(rightend)= (*(2*(OD/2) ^2+Lr^2/e*LN((1+e)/(1-e))))/2	1.46	m
A(total) = A(left end)+A(cylinder)+A(right end)                                 18.051 m
where:  e =  and Le = Ll or Lr
Surface Area

Tab. 10

2609.3	Ibs	1183.5	Kg	We(leftend)=A(leftend)*((t/12)*ws+wi*ti/12)
26907.9	Ibs	12205.2	Kg	We(cylinder)= A(cylinder)*((t/12) *ws+wi*ti/1
2609.3	Ibs	1183.5	Kg	We(rightend)=A(rightend)*((t/12)*ws+wi*ti/12)
1000.0	Ibs	453.592	Kg	Wt. This has been considered as an input value
33126.5	Ibs	15025.9	Kg	We(total)=We(leftend)+We(cylinder)+We(rightend)+Wm

EMPTY WEIGHT OF THE TANK 

Tab.11

Therefore, the total value of empty tank is converted to ton which is 16.5 ton.

Tab.12 shows the volume of tank which is likely to be filled by Hydrogen.

V(left end) =	2.74	ft.^3	V (left end) = (4/3*pi*(ID/2)^2*(Ll-t/12))/2
V(cylinder) =	110.94	ft.^3	V(cylinder) = pi*ID^2/4*Lc
V(right end) =	2.74	ft.^3	V(right end) = (4/3*pi*(ID/2)^2*(Lr-t/12))/2
V(total) =	116.43	ft.^3	V(total) = V (left end) +V(cylinder)+V(right end)
TOTAL	870.97	gal.	V(total) = (V(left end)+V(cylinder)+V(right end))*7.4805

Therefore, the total volume is likely to be converted to m3 which is defined as 24.6631=24600 Litter (L).In addition , it was consider  24.663*39.76kg/ to define the quantity of Hydrogen in 1 tank . Therefore, 980.60kg of hydrogen is likely to be the value of the capacity of the tank.

Weight of full tank.

Wc(left end) =	171.3	lbs.	Wc(left end) = V(left end)*(t/12)*wc
Wc(cylinder) =	6926.3	lbs.	Wc(cylinder) = V(cylinder)*wc
Wc(right end) =	171.3	lbs.	Wc(right end) = V(right end)*wc
Wc(total) =	7268.9	lbs.	Wc(total) = Wc(left end)+Wc(cylinder)+Wc(right end)

Tab. 13 shows the weight of the tank when is filled by Hydrogen.

Therefore, the group has considered the total weight of tank + full content. This means that empty weight +full weight tank where Total =We+Wc = 33126.5 + 7268.9 = 40395.4 Ibs the value is likely to converted by kg and ton which are 18323.4 kg and 20.1 ton. In conclusion, the numbers of the tank have been calculated by the quantity of hydrogen produced and quantity of hydrogen

in 1 tank 374400 kg /980.60kg = 381.80 which is likely to be 382 tanks on the offshore platform.

REFERENCES

• Pressure vessel calculations weights excel.
• Eugene F. Megyese Tulsa Oklahoma pressure vessel inc.1973
• Ahmed Ibrahim*, Yeong Ryu, Mir Saidpour, 2015.
• E. Tzimas et al, 2003.
• Daniel A. Crowl and Scott Tipler, American institute of chemical engineers, 2013
• International Journal of Emerging Engineering Research and Technology Volume 2, Issue 3, June 2014, PP 1-8 ISSN 2349-4395 (Print) & ISSN 2349-4409 (Online).
• Yu Wang et al. / Energy Procedia 29 (2012) 657 – 667.
• IRENA, 2019b. Navigating the way to a renewable-powered future: Solutions to decarbonise shipping. International Renewable Energy Agency, Abu Dhabi.
• ASME pressure vessels & water storage Tanks Highland Tank.
• Sofoklis S. Makridis1,2 ,2016.
•  TRANSPORTATION SYSTEM  Hydrogen can be transported and stored gradually by 4 main methods: ■ Liquid (cryogenic) hydrogen ■ Ammonia ■ Hydrogenated liquid organic hydrogen carrier ■ Compressed gaseous hydrogen.However, it seems to be crucial the process of hydrogenation and dehydrogenation where the lowest cost is dependably on states a reason why gaseous is considered costly effective. Hydrogen has been compressed at 9430.50 Nand stored in tank at high pressure nearly 700 bar at gaseous state. However, the low volumetric density of hydrogen can be considered an issue to storage and transportation; moreover, the distance due to offshore environment. However, hydrogen can be transported by truck, ships and pipelines. Therefore, pipelines have been chosen as the most suitable option due to similarity operation with natural gas and geological site.1.1 Technological option for Transportation system.Transportation System HydrogenNorth Sea has been chosen as geological location for hydrogen production, storage and transportation. However, hydrogen is likely to be transported by pipelines at low pressure as reported by Pilar Blanco-Fernandez, 2017 it is more safe to transport hydrogen  at low pressure.
  

  Site	Water depth	Distance to shore	Quantity
  North Sea, Peterhead	100 m	50 km	374400 kg

   Tab 1 shows the details of the operational field.

  Fig 1. shows the Pipelines system at Peterhead.

  

   

   

  

  1.2 Pipelines transmission system.

  Pipeline transport for compressed gaseous hydrogen is likely to considered in general the most cost-effective approach of transporting large volumes of it by long distances. Furthermore, the transportation can be operated in pure form or be blended into natural gas above the limits or restrictions prescribed by policies regulations or contract regulations. However, certain factors should be considered in pipelines transportation.

  • Velocity – this is where the volume flow rate associated with pressure and temperature is likely to be divided by section area.
  • Gas pressure – the operation pressure inside the pipe.

  1.3 Brittle fracture and environmental damage mechanisms.

  Two main point has been considered: For internal corrosion.

  • Hydrogen Gas Embrittlement (HGE) at ambient temperature

  For external corrosion.

  • Stress Corrosion Cracking (SCC) of line pipe materials in underground environments.

   

   

   

   

   

   

   

   

   

  REFERENCE

  1. https://www.itmpower.com/images/NewsAndMedia/Reports/New_energy_value_chains_Hydrogen_as_an_energy_carrier_DNV-GL November_20.
  2. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/866379/Phase_1_-_OGTC_-_Hydrogen_Offshore_Production.
  3. American Petroleum Institute, “Specification for Line Pipe, API Specification 5L,” American Petroleum Institute, 41st Edition, April 1, 1995.

Ptt Storage System Hydrogen pptx

Storage SYSTEM