BVNBVN TM PEV2 – Boilers

Head Office – Department Technology Equipment - V0 – November 2009

CONTENT

1 – Objectives2 – General description of boilers3 – Classification Rules requirements

1 – Objectives

4Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009

Pressure vessels – Objectives

• To be familiar with Classification Rules regarding boilers

• Study of Classification Rules requirements for boilers

2 – General description of boilers

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Boilers – General description

Boilers could be categorized according to : The intended use :

Main

Auxiliary

The type of heated media :

Steam

Overheated water

Thermal oil

The geometry :

Fire tube boilers

Water tube boilers

Coils boilers

Composite boilers

The type of heat input :

Burner

Exhaust gas

Composite boilers

7Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009

Boilers – General description

Main boiler

• Exclusively steam boilers

• Mostly superheated steam for steam turbine propulsion: LNGC and LPGC

• Seldom saturated steam for alternative piston engines

Auxiliary

• Steam

• Mostly saturated steam for heating purpose of fuel or cargo

• Overheated water

• For heating purpose of fuel or cargo or for accommodations

• Thermal Oil

• For heating purpose of fuel or cargo

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Boilers – General description

Steam

• Pressure is generally between 7 to 80 bar

• Temperature is generally between saturation and 500°C

Overheated water

• Pressure is kept at a value avoiding vaporization with a temperature margin generally between 15 to 30°C

Thermal oil

• Organic or synthetic base able to be heated up to 300- 350°C (at least 50°C below distillation point)

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Boilers – General description

Fire tube boiler

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Boilers – General description

Fire tube boiler type 3 pass wet back

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Boilers – General description

Fire tube boiler type 3 pass semi wet back

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Boilers – General description

FIRE TUBE BOILER

Main usual characteristics

• Pressure is generally between 7 to 20 bar

• Temperature is generally saturation with possible overheating generally less 30°C

• Vaporisation between 50 kg/h to 35 t/h

• Well adapted for power variations due to thermal inertia

• Thermal efficiency > 90% (93% with economizer)

Particulars

• Furnace under external pressure calculated for elastic strength and for buckling with a maximum thickness of 22 mm to avoid excessive thermal gradient

• Large end plates with particular calculation

• Special care for type of welded joints: furnace/end plate & end plate/shell

13Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009

Boilers – General description

WATER TUBE BOILER

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Boilers – General description

WATER TUBE BOILER

Main usual characteristics

• Pressure is generally between 30 to 80 bar

• Generally overheated steam up to 500°C

• Vaporisation of more than 20 t/h

• Very well adapted for power variations

• Thermal efficiency 85%

Particulars

• Internal pressure parts only, tubes only exposed to heat transfer >no thickness limit of drums > no size limit

• Special care for welded joints, in particular longitudinal of drums

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Boilers – General description

Steam Boiler Thermal Oil Heater

COIL BOILER

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Boilers – General description

STEAM COIL BOILER

Main usual characteristics

• Pressure is only depending of the steam system,

• Production of mix steam + water (10% m.m) need separator

• Vaporisation from 250 kg/h to 8 t/h

• Thermal efficiency 90%

• Very well adapted for intermittent use

• Very badly adapted for power variation

Particulars

• “One pass boiler” with volumetric feed water pump

• Internal pressure parts only,

• Tubes only exposed to heat transfer > progressive increase of temperature along the coil > fur deposit localized in one point > good water quality

17Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009

Boilers – General description

THERMAL OIL COIL BOILER

Main usual characteristics

• Pressure is only depending of the system, generally 2 to 6 bar

• Power from 100 kW to 10 MW

• Temperature up to 350°C

• Thermal efficiency 90%

• Well adapted for power variation

• Not well adapted for intermittent use

Particulars

• Single or parallel coils with hydrodynamic circulating pump

• Internal pressure parts only

• Tubes only exposed to heat transfer,

• Risk of calefaction of thermal oil > fluid flow always to be ensured

• Need of an expansion tank under inert gas pressure

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Boilers – General description

COMPOSITE BOILER according geometry

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Boilers – General description

COMPOSITE BOILER according to heating media :

Oil fired burner and/or exhaust gas

3 – Classification Rules requirements for boilers

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Boilers – Part C Ch 1 Sec 3

• Classification Rules requirements to be studied in general

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Boilers – Part C Ch 1 Sec 3

• Classification Rules requirements to be specially studied

Part C Chapter 1 Section 3

Article 1 « General »

Article 4 « Fabrication and welding »

Article 7 « Material test, workshop inspection and testing, certification »

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Boilers – Part C Ch 1 Sec 3

Documentation to be submitted for type approval or case-by-case approval by HO or LPO

24Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009

Boilers – Part C Ch 1 Sec 3

Documentation to be submitted for type approval or case-by-case approval by HO or LPO

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Boilers – Part C Ch 1 Sec 3

Production phase - Boilers individual certificate

Pay attention to BV certificates for Class I pressure vessels

BV Product certificate for materials of pressure parts

Work’s certificate for materials of pressure parts

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Boilers – Part C Ch 1 Sec 3

Production phase - Boilers individual certificate

Pay attention to BV certificates

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Boilers – Part C Ch 1 Sec 3

Production phase – Boilers individual certificate

• Typical tasks for survey :

- Check availability of reviewed drawings (as per type approval as relevant)

- Check materials and components certificates, as relevant

- Check Welding Procedure Specification and Welding Procedure Qualification Records

- Check welders certificates

- Check fabrication conditions (cleanliness, welding preparation etc.)

- Check non-destructive testing operators certification

- Witness hydraulic pressure testing

- General visual examination

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Boilers – Part C Ch 1 Sec 3

Characteristics for certificates, as applicable :

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Boilers – Part C Ch 1 Sec 3

Typical tasks for survey, as applicable :

30Bureau Veritas S.A. internal use only – Boilers – BVN TM PEV2 – V0 – November 2009