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GB/T 18442.6-2011 English PDF (GBT18442.6-2011)

GB/T 18442.6-2011 English PDF (GBT18442.6-2011)

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GB/T 18442.6-2011: Static vacuum insulated cryogenic pressure vessel -- Part 6: Safety device requirements

This part specifies the basic safety device requirements of the static vacuum insulated cryogenic pressure vessel. The application scope in this part is the same as that in Part 1 of this standard.
GB/T 18442.6-2011
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 23.020.40
J 76
Partially replacing GB 18442-2001
Static Vacuum Insulated Cryogenic Pressure Vessel -
Part 6. Safety Device Requirements
ISSUED ON. NOVEMBER 21, 2011
IMPLEMENTED ON. MAY 1, 2012
Issued by. General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ);
Standardization Administration (SAC) of the People's
Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References... 5
3 Terms and Definitions ... 6
4 Safety Accessories and Charge and Discharge Accessories ... 6
Appendix A (Normative) Calculation of the Safety Relief Capacity ... 14 Foreword
"Static Vacuum Insulated Cryogenic Pressure Vessel" (GB/T 18442) comprises 6 parts. - Part 1. General Requirements;
- Part 2. Material;
- Part 3. Design;
- Part 4. Fabrication;
- Part 5. Inspection and Test;
- Part 6. Safety Device Requirements.
This part is the sixth part of GB/T 18442.
This part refers to "Cryogenic Vessels - Static Vacuum-insulated Vessels - Part 1. Design, Fabrication, Inspection and Tests" (ISO 21009-1. 2008) (English Edition) and "Cryogenic Vessels - Pressure-relief Accessories for Cryogenic Service - Part 3. Sizing and Capacity Determination" (ISO 21013. 2006) (English Edition).
This part replaces the "safety devices and accessories" in Section 6.7 of "Cryo- insulation Pressure Vessels" (GB 18442-2001) and partial contents in it. Compared with "Cryo-insulation Pressure Vessels" (GB 18442-2001), changes in this part are as follows.
- Calculation of safety relief capacity (Appendix A) was added;
- "Emergency shutoff device" (Section 4.4), "charge and discharge valve" (Section 4.8), "charge and discharge rubber lined hose and quick joint" (Section 4.9) were added.
This part was proposed and is under the jurisdiction of National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
Drafting organizations of this part. China International Marine Containers (Group) Co., Ltd., Shanghai Gas Industry Association, Chart Cryogenic Engineering Systems (Changzhou) Co., Ltd., China Special Equipment Inspection and Research Institute, Shanghai Huayi Group Equipment Engineering Co., Ltd., Sanctum Cryogenic Static Vacuum Insulated Cryogenic Pressure Vessel -
Part 6. Safety Device Requirements
1 Scope
1.1 This part specifies the basic safety device requirements of the static vacuum insulated cryogenic pressure vessel (hereinafter referred to as "cryogenic vessel"). 1.2 The application scope in this part is the same as that in Part 1 of this standard. 2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendment) applies. GB 150 Steel Pressure Vessels
GB 567 Bursting Disc Devices
GB/T 12241 Safety Valves - General Requirements
GB/T 14525 General Specification for Corrugated Metal Hose Assemblies
GB/T 18442.1 Static Vacuum Insulated Cryogenic Pressure Vessel - Part 1. General Requirements
GB/T 18442.2 Static Vacuum Insulated Cryogenic Pressure Vessel - Part 2. Material GB/T 18442.3 Static Vacuum Insulated Cryogenic Pressure Vessel - Part 3. Design GB/T 18442.4 Static Vacuum Insulated Cryogenic Pressure Vessel - Part 4. Fabrication
GB/T 18442.5 Static Vacuum Insulated Cryogenic Pressure Vessel - Part 5. Inspection and Test
3 Terms and Definitions
For the purpose of this part, terms and definitions established in GB 150, GB/T 18442.1, GB/T 18442.2, GB/T 18442.3, GB/T 18442.4 and GB/T 18442.5 apply.
4 Safety Accessories and Charge and Discharge
Accessories
4.1 General requirements
4.1.1 Safety accessories include safety relief devices (safety valve, bursting disc device and safety relief device with safety valve and bursting disc combined), explosion-proof device of the outer shell, emergency shutoff device, liquid level meter, thermometer, pressure gauge, flame arrester and static conductive device. 4.1.2 Charge and discharge accessories include charge and discharge valve, quick joint and charge and discharge rubber lined hose.
4.1.3 Fabrication organizations of safety relief device, emergency shutoff device, charge and discharge rubber lined hose and quick joint shall possess manufacturing license issued by the national safety supervision and administration department for special equipment.
4.1.4 Safety accessories and charge and discharge accessories shall meet the requirements of corresponding standard; moreover, they shall be provided with product quality certificate.
4.2 Safety relief device of inner vessel
4.2.1 Arrangement requirements for safety relief device of inner vessel 4.2.1.1 For arrangement of safety relief device for inner vessel, two most basic external conditions, non-fire condition [Conditions a) to f) in Article 4.2.2.2 of this part]and fire condition [Conditions g) and h) in Article 4.2.2.2, including other unpredictable external heat source that may have high temperature of 922K] shall be taken into consideration.
4.2.1.2 The most basic requirements where it is considered according to non-fire condition
At least two safety valves shall be arranged for the inner vessel as shown in Figure 1. 1- switching valve;
2- safety valve;
3- bursting disc device.
Figure 2 -- Arrangement of Safety Relief Device
4.2.1.4 The safety valve shall meet the requirements of GB/T 12241.
4.2.1.5 The bursting disc device shall meet the requirements of GB 567. 4.2.1.6 The safety relief device shall be adopted with spring safety valve or combination device of safety valve and bursting disc.
4.2.1.7 Arrangement of the safety relief device shall meet the following requirements. a) Inlet pipe of the safety relief device shall be arranged at the top space with volume less than 2% above liquid level of the tank and vertical to top of the vessel; moreover; it shall be close to the longitudinal and lateral centers as possible; b) Combination device of safety valve and bursting disc may be selected for cryogenic vessel storing non-explosive medium;
c) Combination device of double safety valves shall be adopted for cryogenic vessel storing explosive medium;
d) Exhaust of gas shall be unblocked, and the gas exhausted for pressure relief cannot impact the vessel and main load-carrying structure members directly; e) Flame arrester arranged for cryogenic vessel storing explosive medium shall have no influence on required relief capacity of the safety relief device; f) Accumulation of rain and foreign materials shall be avoided at the outlet; moreover, entering of any foreign material is avoided;
g) It shall be able to bear pressure in the vessel, overpressure that may arise and dynamic load including impact force of liquid.
4.2.1.8 The safety relief device shall be provided with a clear and permanent mark covering at least the following items.
a) Action pressure of the safety relief device;
b) Specified exhaust capacity;
together.
4.2.2.4 Calculation method for operating conditions d), e) and f) in Article 4.2.2.2 is not specified in Appendix A. The designing personnel shall distinguish whether these operating conditions are existed according to actual conditions. Where they are existed, influence of these operating conditions shall be estimated fully according to thermodynamic basic theory.
4.2.2.5 Where it can be judged that the vessel is impossible to be subject to fire, safety relief device of the inner vessel shall meet the safety relief requirements where several operating conditions in Items a) to f) of Article 4.2.2.2 may exist simultaneously. 4.2.2.6 Where it can be judged that the vessel may be subject to fire, safety relief capacity is considered according to operating condition g) in Article 4.2.2.2 generally, however, possibility of extreme operating condition h) is also sufficiently studied. 4.2.2.7 Fire condition is not considered generally for vessel installed below ground. 4.3 Explosion-proof device of outer shell
4.3.1 Arrangement requirements for explosion-proof device of outer shell 4.3.1.1 The outer shell shall be arranged with explosion-proof device with relief pressure less than or equal to 0.05MPa, the relief capacity shall be able to limit pressure of the interspace less than or equal to 0.1MPa.
4.3.1.2 The explosion-proof device shall be atmosphere-corrosion resistant, the material shall be appropriate to the ambient temperature.
4.3.1.3 The explosion-proof device shall be able to avoid blocking of insulated material.
4.3.2 Exhaust area for explosion-proof device of the outer shell
Exhaust area for explosion-proof device of outer shell is greater than or equal to the product of inner-vessel geometric volume (m3) and 340mm2/m3 but no greater than 5000mm2.
4.4 Emergency shutoff device
4. 4.1 Arrangement requirements for emergency shutoff device
4.4.1.1 For vessel storing explosive medium or extreme-toxicity medium or highly hazardous medium, valve which can be quickly closed down or emergency shutoff pressure test, the pressure holding time shall be greater than or equal to 10min. 4.5 Liquid level meter
4.5.1 The liquid level meter shall be selected correctly according to medium, operating pressure and temperature.
4.5.2 The liquid level meter shall be flexible and accurate with firm structure, its precision grade shall be greater than or equal to Grade 2.5.
4.5.3 Glass sheet (pipe) liquid level meter or other liquid level meter made of friable materials shall not be used.
4.5.4 For explosive medium, explosion-proof liquid level meter shall be adopted, moreover, anti-leakage device shall be provided with.
4.5.5 The liquid level meter shall be installed on position convenient for observation. 4.5.6 The design organization shall provide data for indication of the corresponding relationship between scale volume.
4.6 Pressure gauge
4.6.1 The pressure gauge shall be compatible with the shipping medium.
4.6.2 Measuring range of the pressure gauge is 1.5~3.0 times of the operating pressure, the precision grade is greater than or equal to Grade 2.5 and diameter of the dial is greater than or equal to 100mm.
4.6.3 Position for installment shall be convenient for observation and cleaning of operation personnel; and influences of freezing and vibration shall be avoided. 4.7 Static conductive grounding device
4.7.1 For cryogenic vessel storing explosive medium, conductibility of its connections such as tank, piping, valve and support shall be in good condition, moreover, reliable static conductive connecting terminal shall be arranged.
4.7.2 The resistance between tank and grounding wire shall be less than or equal to 10??.
4.8 Charge and discharge valve
The charge and discharge valves shall meet the following requirements.
Appendix A
(Normative)
Calculation of the Safety Relief Capacity
A.1 Calculation of the total heat flow introduced from the hot wall (outer shell) to the cold wall (inner vessel)
A.1.1 Non-fire condition
A.1.1.1 Where the insulation system (jacket and insulated material) is in good condition and under the normal vacuum state; the outside temperature is ambient temperature and the inner vessel temperature is saturation temperature of the stored medium under the relief pressure, the calculation methods of the heat flow introduced from the hot wall to the cold wall that need to be considered are as follows. a) Under the normal vacuum state, the heat flow introduced through insulated material is calculated according to Formula (A.1).
Hi.v=Ui.v ??Ai.m ?? (Ta- Td) ... (A.1)
Where,
Hi.v - the heat flow introduced through insulated material under the normal vacuum state, W;
Ui.v - the total heat transfer coefficient of the interspace-insulated material under the normal vacuum state, W/m??K;
Ui.v=
i.v
Where,
i.v?? - the average thermal conductivity of the insulated material between the temperature range Ta~Td under the normal vacuum state, W/m??K;
it - the nominal thickness of the insulated material, m;
Ai.m - the arithmetic average for the internal and external surface area of the insulated layer, m2;
Td - the surface temperature of the vessel or heat transfer member cold end corresponding to a certain cryogenic medium, K;
As for the subcritical fluid, Td is the saturation temperature of the medium under relief pressure, K;
For critical or supercritical fluid, Td is determined according to Note 1. c) The heat flow introduced through the limit member arranged to restraint the longitudinal (axial) displacement of the inner vessel is calculated according to Formula (A.3).
Hb.l=Nb.l
l.t
da
TT ?€? ... (A.3)
Where,
Hb.l - the heat flow introduced through the limit member arranged to restraint the longitudinal displacement of the inner vessel, W;
Nb.l - the longitudinal limit member number of the inner vessel;
Rt.l - the total thermal resistance of the longitudinal limit member, K/W; Rt.l= b.l t.l
b b.l tu t.l?? ?? A
L L
?€???? ???
Where,
Lb.l - the longitudinal non-metal limit member length of the inner vessel, m; Lt.l - the longitudinal metal limit member length of the inner vessel, m; b?? - the thermal conductivity for fabricating the longitudinal non-metal limit member of the inner vessel, W/m??K;
tu?? - the thermal conductivity for fabricating the longitudinal metal limit member of the inner vessel, W/m??K;
Ab.l - the sectional area of the longitudinal non-metal limit member of the inner vessel, m2;
Td - the surface temperature of the vessel or heat transfer member cold end corresponding to a certain cryogenic medium, K;
As for the subcritical fluid, Td is the saturation temperature of the medium under relief pressure, K;
For critical or supercritical fluid, Td is determined according to Note 1. e) The heat flow introduced through the vacuum interspace pipeline is calculated according to Formula (A.5).
Htube= t tubexi a d gas tubexi a d
i i1
( ) ( )[ ]
A T T A T T
L L
??? ???
??? ?€? ??? ?€??€???? ... (A.5)
Where,
Htube - the heat flow introduced through vacuum interspace pipeline, W; ??t - the average thermal conductivity through the vacuum interspace pipeline material between the temperature range Ta~ Td, W/m??K;
a c
a d
?? ??
T T
Where,
??c - the thermal conductivity of the vacuum interspace pipeline material at the cold end (saturation temperature of the cryogenic medium under relief pressure), W/m??K;
??a - the thermal conductivity of the vacuum interspace pipeline material at the hot end, W/m??K;
Atube??i - the cross-sectional area of the No. i tube of the inner vessel penetrating the vacuum interspace, i= 1, 2, ..., n, m2;
Li - the length of the No. i tube in the vacuum interspace, m;
??gas - the thermal conductivity of the stored gas, W/m??K;
Ta - the maximum ambient temperature of the insulated vessel outside under non-fire condition, K;
Ta - the maximum ambient temperature of the insulated vessel outside under non-fire condition, K;
Td - the surface temperature of the vessel or heat transfer member cold end corresponding to a certain cryogenic medium, K;
As for the subcritical fluid, Td is the saturation temperature of the medium under relief pressure, K;
For critical or supercritical fluid, Td is determined according to Note 1. A.1.1.4 Where the insulation system is in good condition but the interspace not under vacuum state; the outside temperature is ambient temperature and the inner vessel temperature is saturation temperature of the stored medium under relief pressure, the total heat flow introduced from the hot wall to the inner vessel is calculated according to Formula (A.8).
H3=Hi.l+Hs.t+Htube+Hb.l+Hb.t ... (A.8)
Where,
H3 - the total heat flow introduced from the hot wall to the inner vessel where the insulation system is in good condition but the interspace not under vacuum state; the outside temperature is ambient temperature and the inner vessel temperature is saturation temperature of the stored medium under relief pressure, W;
Hi.l - the heat-leak flow input through the insulated material where the interspace is not under vacuum state, W;
Hi.l=Ui.l??Ai.m?? (Ta-Td)
Ui.l - the total heat transfer coefficient of the insulated material at ambient temperature under atmospheric pressure, W/m2??K;
Ui.l=
i.l
??i.l - the average thermal conductivity of the insulated material filled with or adsorbing air/ medium gas under atmospheric pressure between the temperature range Ta~ Tb where the interspace is not under vacuum state, W/m??K;
ti. - the nominal thickness of the insulated material, m;
Ai.m - the arithmetic average for the internal and external surface area of the insulated range Td~922K where the outside of the vacuum insulated cryogenic vessel is subject to fire or 922K high temperature and the interspace is not under vacuum state; and the insulated material is filled with medium gas or air under atmospheric pressure but still able to effectively prevent heat conduction, heat convection and heat radiation, the larger value of gas or air is taken, W/m??K;
ti - the nominal thickness of the insulated material, m;
At - the area average of the inner vessel and outer shell, m2;
For horizontal vessel with hemispherical head, At= ?€D0L;
For horizontal vessel with ellipsoidal head, At= ?€D0 (L+0.3D0);
For vertical vessel, At= ?€D0h1;
L - the value calculated by total length of the outer shell minus average of interspace thicknesses on both ends at central axis of the tank, m;
D0 - the diameter average of the inner vessel and outer shell, m;
h1 - the design maximum liquid level height, m;
A.1.2.2 Where the jacket outside of the vacuum insulated cryogenic vessel is subject to fire or 922K high temperature and the insulation system is totally damaged, the total heat flow introduced from the hot wall to the inner vessel is calculated according to Formula (A.10).
H5=7.1??104??Ar0.82 ... (A.10)
Where,
H5 - the total heat flow introduced from the hot wall to the inner vessel where the jacket outside of the vacuum insulated cryogenic vessel is subject to fire or 922K high temperature and the insulation system is completely damaged, W;
Ar - the external surface area of the inner vessel, m2;
For horizontal vessel with hemispherical head, At= ?€D0L;
For horizontal vessel with ellipsoidal head, At= ?€D0 (L+0.3D0);
For vertical vessel, At= ?€D0h1;
vg - the specific volume of saturated gas medium in relief pressure, m3/kg; ve - the specific volume of saturated liquid medium in relief pressure, m3/kg; Hi - the total heat flow from hot wall (jacket) introduced to cold wall (inner vessel), corresponded with i=1, 2, 3, 4 and 5, they are calculated respectively by Formulas (A.6), (A.7), (A.8), (A.9) and (A.10), W;
q - the vaporization latent heat of liquid medium in relief pressure, kJ/kg; A.2.3 Where gas relief pressure of safety relief device is greater than the critical pressure of medium, the calculation formula of the inner vessel's safe-relief mass-flow rate in (A.11) shall be revised, i.e. it shall be calculated according to Formula (A.13). Ws.i?€?= '
6.3
Hi ... (A.13)
Where,
Ws.i?€? - the safety relief capacity of vacuum insulation pressure vessel, where gas re...

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