emaco group – steel work department

Design and analysis of above-ground full containment LNG storage tanks

• Development of the world's largest above ground LNG

tank • Static, dynamic, thermal and nonlinear analysis • Strict design requirements met

emaco group develops and continually improves its range of above ground full containment Liquified Natural Gas tanks. With the assistance of emaco engineering consultancy services LNG storage tank sizes of 140,000m3 were initially developed but now, using emaco group, an above ground full containment LNG tank with a capacity of 200,000m3 has been analysed and optimised . When it is constructed in 2006 it will be the largest above ground full containment LNG storage tank in the world.

Tank development

Over the years EMACO-Tech has developed two distinct types of above-ground post-tensioned concrete containment tanks. One involves the use of a proprietary inner membrane system, and the other comprises a steel nickel inner tank lining. Both are of a 140,000m3 capacity and have been installed at the Pyeongtaek facilities in South Korea.

With the use of emaco group EMACO-Tech has now developed a 200,000m3 above ground tank for the Pyeongtaek facility. Similar in nature to its smaller brother it has a 37.6m high nickel steel inner tank of 84m diameter insulated from a 86.4m inside diameter post-tensioned concrete wall. The steel tank sits on a concrete base slab supported by small diameter piles at close centres. The overall tank height to the top of the roof slab is 52.8m.

Analyses undertaken

In analysing and developing its range of tanks EMACO-Tech performs numerous finite element analyses with emaco group including:

• Static analysis • Wind loading • Modal and seismic analysis • Temperature modelling • Leakage modelling • Prestress / post-tensioning • Burn-out modelling • Relief valve heat flux modelling • Soil-structure interaction

Static analysis

emaco group – steel work department

combinations then allow the effects of the multiple loadcases to be assessed.

Modal analysis

3D shell element modelling and eigenvalue analysis of the LNG tank outer shells and pressure relief platforms involves an examination of both the uncoupled and coupled response of the two structures. Lumped mass modelling is used for fluid/structure interaction of the LNG and for soil/structure interaction of the pile arrangements.

Wind load modelling Seismic analysis

3D shell element modelling is used to carry out wind load analysis of the LNG tank outer shell. For this analysis, half-models can often be used due symmetry of both tank geometry and loading. The wind load is varied around the circumference of the outer walls using a Fourier distribution providing a normal pressure on the forward face of the structure and a suction to the rear face.

Interactive Modal Dynamics techniques are used in the calculation of the dynamic seismic response. Operational Basis Earthquake (OBE) and Safe Shutdown Earthquake analysis assessments are also run to satisfy code requirements. The generated data from the structural analysis is integrated to obtain base shear forces and bending moments in the wall.

Thermal modelling

For thermal modelling, 2D axisymmetric solid field and continuum elements are used and a semi-coupled steady state thermal analyses of LNG tank outer walls with insulation is performed. For this, an initial stress-free temperature is applied to all elements, and combinations of environmental conditions are considered for both the air and base temperatures. Results plots of hoop stresses in the top and bottom corners caused by a steady state thermal load are produced.

emaco group – steel work department

Leakage modelling

Leakage modelling analysis investigates the effect of LNG spillage from the inner steel tank onto the Polyurethane Foam (PUF) insulation on the inside of the outer concrete tank at five different heights. The tank insulation is assumed to have been completely destroyed up to each level of the LNG under consideration. 2D axisymmetric solid field and continuum elements are used to model the tank outer walls and insulation down to the top of each leakage level. A semi-coupled steady state thermal analysis is carried out to assess the effects of the leakage.

Modelling prestress tensioning

Large temporary openings in the wall mean that it is necessary to limit the effects of stress concentration caused by prestress forces. Loadings for each set of cables, both horizontally and vertically, are defined and assigned in separate load cases. These loadings can then be combined in different ways to achieve the required prestress sequence and/or loading pattern. Section

slicing of the model is used to obtain axial forces and bending moments in the walls around the opening for selected load combinations.

Burn-out modelling

Modelling of a burn-out scenario involves 2D axisymmetric solid field elements and transient thermal analyses of the LNG tank outer walls. The tank roof and insulation layers (except any PUF layer), are

assumed to have been destroyed, and are not included in the analysis. Steady state conditions are initially applied for a specified time. To model the burn-out situation, a temperature load of a specified peak temperature reducing to -170°C over a distance of 1.5m is moved down the inside of the tank at a constant speed for the burn-out time under consideration.

Relief valve heat flux modelling

With relief valve heat flux modelling, the tank bases are normally excluded from an analysis because they are considered to be remote from the heat flux loading. 3D solid field and continuum elements are used for a semi-coupled transient thermal analyses of a segment of an LNG tank.

An initial stress-free temperature is applied to all elements and steady state conditions are established for an internal temperature of –170°C and a specified mean annual external temperature. A heat flux is then be applied to a specified region on the top of the roof for the number of time steps under consideration.

ACTIVITIES

STORAGE TANKS

Due to customer requirements, all storage tanks we have designed and fabricated up to date are to API Std 650 (Including App. D, G and K) and API Std 620. However, other internationally accepted codes may be specified. For cone roof, dome rofe and floating roof tanks per API Std 650, our maximum fabrication capacity is above

emaco group – steel work department 150.000 m³ .

Low pressure cold storage tanks to API Std 620 for LPG, Ammonia and similar products are also in our line of activity. Two ammonia tanks with 15.000 m³ capacity and -36°C and two liquid oxygen tanks of 1000 m³ capacity and -193°C service temperature have been fabricated and constructed in Turkey by our company.

We are experienced to supply turn-key tank farms inclusive of engineering, fabrication and construction, piping and civil works, if required.

15.000 m³ Capacity, -34°C NH3 Storage Tanks

Gasholder & Spherical Tank 64.000 m³ Capacity Crude Oil Tank

Baku-Tbilisi-Ceyhan Crude Oil Pipeline Project Irak-Turkey Crude Oil Pipeline

Ceyhan Marine Terminal Onshore And Offshore Yumurtalık Terminal7x150.800 m³ Crude Oil Tanks 5x135.000 m³ Crude Oil Tanks

Baku-Tbilisi-Ceyhan Crude Oil Pipeline Project, Ceyhan Marine Terminal Onshore And Offshore

7x150.800 m³ Crude Oil Tanks

ACTIVITIES

SPHERICAL TANKS

Spherical tanks for storage of LPG, propane, butane, NH3, ethylene, chlorine, etc. are designed, fabricated and constructed according to German AD-2000 or ASME Sec. VIII Div. 1 and Div. 2 and latest editions of local and international earthquake regulations.

We have supplied many of the spherical tanks in Europe, with capacities ranging from 500 m³ to 6.000 m³ for various products. We are capable of delivering turn-key LPG plants with storage, loading, unloading, pumping, metering and control facilities.

3500 m³ capacity LPG storage tanksSeveral spherical tanks designed and fabricated by our company are also under operation in Pakistan, Libya, Iran and Cyprus.

In addition, some spherical tanks have been reinforced after 1999 earthquake in Turkey.

emaco group – steel work department

3 x 5850 m³ Ammonia Spheres

1000 m³ and 3500 m³ Capacity LPG Spheres

2 x 3700 m³ MTBE Spheres for Iran2 x 3750 m³ VCM Spheres for Pakistan

ACTIVITIES

PRESSURE VESSELS

We design and fabricate almost any size and shape of pressure vessels. Our reference list indicates various drums and reactors manufactured for various industries.

If the size or weight of any vessel exceeds transportation limits, we prefabricate it in pieces and complete fabrication at the job-site.

All types of carbon steel, stainless steel and carbon steel clad with stainless steel, monel, brass and other clad materials are used for the fabrication of equipments mentioned above.

150 m³ capacity Gas Oxygen Drum P=44 kg/cm²

Pressure vessels up to 6.500 mm dia and 100 mm steel thickness to any specified length can be fabricated.

Autoclave

emaco group – steel work department Absorber for TPAO Kuzey Marmara and Degirmenköy Underground Storage

Cold Separator for TPAO Kuzey Marmara and Degirmenköy Underground Storage

of Natural Gas Project of Natural Gas Project

ACTIVITIES

HEAVY STRUCTURAL STEEL CONSTRUCTION

Blast furnace supporting structure and other heavy steel construction works are in our manufacturing programme. We can mention as an example Turkish Petroleum Corporation Izmir Refinery reactor regenerator construction and ERDEMIR blast furnace supporting construction (6600 ton), as well as steel structures for Iskenderun and Afsin Elbistan-B power plants.

We also fabricate steel ladles and galvanization baths to steel industry.

Steel constructions of tyre curing presses are also included in our manufacturing programme. Steel Structures

Steel Ladle

Power Plant Steel Structures Galvanizing Bath Tyre Curing Press