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GB/T 18442.3-2019 PDF in English


GB/T 18442.3-2019 (GB/T18442.3-2019, GBT 18442.3-2019, GBT18442.3-2019)
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GB/T 18442.3-2019: PDF in English (GBT 18442.3-2019)

GB/T 18442.3-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.40
J 76
Replacing GB/T 18442.3-2011
Static Vacuum Insulated Cryogenic Pressure Vessels - Part
3: Design
ISSUED ON: DECEMBER 10, 2019
IMPLEMENTED ON: DECEMBER 10, 2019
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 6 
2 Normative References ... 6 
3 Terms and Definitions ... 7 
4 General Requirements ... 9 
5 Design Documents ... 9 
6 Loads ... 11 
7 Temperature ... 15 
8 Pressure ... 15 
9 Welded Joint Coefficient ... 16 
10 Allowable Stress ... 16 
11 Corrosion Allowance ... 17 
12 Thickness of Tank Body ... 17 
13 Filling Rate ... 18 
14 Vacuum Insulation Performance Indicators ... 18 
15 Vacuum Performance of Annular Space ... 21 
16 Pressure Resistance Test... 22 
17 Leakage Test ... 24 
18 Structural Design ... 24 
Appendix A (normative) Risk Assessment Report ... 33 
Appendix B (informative) Thermodynamic Data of Commonly Seen Refrigerated
Liquefied Gases ... 35 
Static Vacuum Insulated Cryogenic Pressure Vessels - Part
3: Design
1 Scope
This Part of GB/T 18442 specifies the basic requirements for the design documents, design
parameters, performance parameters and structural design of static vacuum insulated cryogenic
pressure vessels (hereinafter referred to as “cryogenic vessels”).
This Part is applicable to cryogenic vessels that simultaneously satisfy the following conditions:
a) The working pressure of the inner vessel is not less than 0.1 MPa;
b) The geometric volume is not less than 1 m3;
c) The thermal insulation mode is vacuum powder insulation, vacuum composite
insulation or high-vacuum multi-layer insulation;
d) The storage medium is refrigerated liquefied gas with the standard boiling point not
lower than 196 C.
This Part does not apply to cryogenic vessels of the following scopes:
a) The material of the inner vessel and outer shell is non-ferrous metal or non-metal;
b) Spherical structure;
c) Stacked thermal insulation mode;
d) Mobile;
e) Store refrigerated liquefied gas medium with the standard boiling point not lower than
196 C;
f) The storage medium is toxic gas in accordance with the stipulations of GB 12268;
g) There are special requirements for national defense and military equipment.
2 Normative References
The following documents are indispensable to the application of this document. In terms of
references with a specified date, only versions with a specified date are applicable to this
document. In terms of references without a specified date, the latest version (including all the
modifications) is applicable to this document.
Filling rate refers to the ratio of the liquid volume of the refrigerated liquefied gas filled in the
cryogenic vessel to the geometric volume of the inner vessel.
3.3 Specified Filling Rate
Specified filling rate refers to the ratio of the liquid volume when the filled liquid reaches the
highest liquid level specified in the design to the geometric volume of the inner vessel when
the cryogenic vessel is filled.
3.4 Holding Time
Holding time refers to the time it takes for the inner vessel to rise from the ambient atmospheric
pressure to the set pressure of the safety relief device when filling refrigerated liquefied gas in
accordance with the specified filling rate, after the refrigerated liquefied gas standing still inside
reaches thermal equilibrium with the external ambient temperature under the atmospheric
pressure, the liquid is filled to the specified filling rate, and after the gas phase valve is closed.
It is converted into the time at the standard atmospheric pressure (1.01325  105 Pa) and the set
ambient temperature (20 C).
NOTE: it is expressed in (h).
3.5 Static Evaporation Rate
Static evaporation rate refers to the percentage of the mass of the refrigerated liquefied gas lost
by natural evaporation within 24 h after the cryogenic vessel stands still to achieve thermal
equilibrium at the specified filling rate, to the mass of the refrigerated liquefied gas under the
effective volume of the inner vessel. It is converted into the evaporation rate at the standard
atmospheric pressure (1.01325  105 Pa) and the set ambient temperature (20 C).
3.6 Annular Space Vacuum Degree
Annular space vacuum degree refers to the absolute pressure of gas in the annular space in the
cryogenic vessel.
3.7 Sealing-off Vacuum Degree
Sealing-off vacuum degree refers to the vacuum degree when the vacuum annular space
pressure is relatively stable at room temperature after the vacuuming of the tank annular space
is completed and the vacuuming interface is sealed off.
3.8 Leakage Rate of Vacuum Annular Space
Leakage rate of vacuum annular space refers to the amount of gas leaking into the vacuum
annular space per unit time.
3.9 Outgassing Rate of Vacuum Annular Space
Outgassing rate of vacuum annular space refers to the amount of gas released per unit time from
the material in the vacuum annular space and the surface of the vessel wall, etc.
3.10 Outgassing and Leakage Rate of Vacuum Annular Space
Outgassing and leakage rate of vacuum annular space refers to the sum of the leakage rate of
vacuum annular space and the outgassing rate of vacuum annular space.
4 General Requirements
4.1 In addition to the requirements of this Part, the design of cryogenic vessels shall also comply
with the stipulations of TSG 21 and GB/T 150.3.
4.2 The design organization shall rigorously follow the design conditions of the cryogenic
vessels provided by the design entrusting party, and comprehensively consider all relevant
factors, failure modes and sufficient safety margins, so as to ensure that the cryogenic vessels
have sufficient strength, stiffness, stability and corrosion resistance. Meanwhile, the strength
requirements for the welded joints between the main load-bearing components, such as: annular
space supports, supports and lifting lugs of the cryogenic vessels, and the tank body shall also
be considered, so as to ensure the safety of the cryogenic vessels within the design service life.
4.3 The layout of the tank body, piping, safety accessories, instruments, and loading and
unloading accessories shall satisfy the requirements for application and safety.
4.4 The basic content of the risk assessment report shall comply with the stipulations of
Appendix A. The thermodynamic data of commonly-seen refrigerated liquefied gas is shown
in Appendix B.
5 Design Documents
5.1 The design documents of the cryogenic vessels shall at least include the following items:
a) Risk assessment report, including the main failure modes and risk control in the stages
of design, manufacture and application, etc.;
b) Design specification, including the main physical and chemical properties of the
filling medium (serial No., name, category, and saturated vapor pressure and density
corresponding to the working temperature, etc.), hazardous characteristics, limited
components of mixed media and limited content requirements of detrimental
impurities, as well as compatibility with tank body materials, etc. In addition, the
selection of design specifications and standards, the determination principles of main
design structures, the determination principles of main design parameters, the
selection of materials, the selection of safety accessories, the selection of instruments,
and loading and unloading accessories, and the selection of self-pressure boosters
shall be elaborated;
h) Design service life of the cryogenic vessels;
i) Requirements for pressure resistance test and leakage test;
j) Manufacturing requirements, including requirements for non-destructive testing, heat
treatment (if necessary), surface cleaning, nitrogen or inert gas replacement, as well
as outer shell surface treatment and coating, etc.;
k) Tank body insulation mode, vacuum insulation performance indicators and annular
space vacuum performance indicators, etc.;
l) Specifications, performance parameters and connection modes of tank safety
accessories, instruments, and loading and unloading accessories;
m) Orientation, specifications and connection flange standards of nozzles, etc.;
n) Location of product nameplate;
o) Requirements for packaging, transportation and installation.
5.3 The piping system drawing shall at least indicate the following contents:
a) The standards, on which, the design and manufacture of the piping system are based;
b) Design parameters, including design temperature, design pressure and welded joint
coefficient, etc.;
c) Material designation and material standard No. and specifications of the stress-
bearing elements of the piping;
d) Models, specifications, performance parameters, connection modes and nozzle
orientations of safety accessories (including piping overpressure relief device),
instruments, and loading and unloading accessories, etc.;
e) Requirements for non-destructive testing;
f) Requirements for pressure resistance test;
g) Requirements for leakage test.
6 Loads
6.1 Overall Requirements
The cryogenic vessels shall be able to withstand mechanical loads (including pressure load,
gravity load, inertial force load and dynamic load) and thermal stress loads under various
possible working conditions, such as: normal operation and empty tank transportation, etc. In
addition, the most demanding combination of these loads that may occur shall also be
considered. Meanwhile, structural fatigue failures due to pressure fluctuations of the inner
vessels within the design service life shall be considered.
6.2 Design Load of Inner Vessel
6.2.1 The following loads shall be considered for the pressure load:
a) Internal pressure, external pressure or maximum differential pressure;
b) When the storage volume reaches the specified filling rate, the static pressure of the
liquid column generated by the medium. The static pressure of the liquid column is
calculated in accordance with the density of the medium at the boiling point under the
standard atmospheric pressure.
6.2.2 The following loads shall be considered for the gravity load:
a) Self-weight of the inner vessel and the gravity load of the thermal insulation material
and annular space piping and other accessories attached to the inner vessel;
b) Under normal working conditions or under pressure resistance test conditions, the
gravity load of the medium contained in the inner vessel.
6.2.3 The loads caused by the following items shall be considered for the dynamic load:
a) When the inner vessel is filled with liquid, the impact force of the liquid flow on the
inner vessel;
b) Impact load caused by rapid fluctuations of the medium pressure;
c) Seismic load.
6.2.4 The thermal stress load shall at least take into account the uneven strain load caused by
the temperature gradient and the piping reaction force caused by the thermal expansion or cold
contraction of the inner vessel and the annular space piping under the following working
conditions:
a) During the cooling of the inner vessel from the ambient temperature to the working
temperature, the load that the inner vessel bears at the support point.
b) The reaction force exerted by the piping on the inner vessel due to the thermal
expansion or cold contraction of the inner vessel and the annular space piping. In
addition, at least the following three working conditions shall be considered:
1) pre-cooling conditions: the inner vessel is in a hot state, the annular space piping
is in a cold state and the outer shell is in a hot state;
2) filling and liquid discharge conditions: the inner vessel and annular space piping
are in a cold state, and the outer shell is in a hot state;
b) When hoisting the empty tank, calculate the inertial force load on the lifting lug of
the tank body. The load coefficient shall comply with the stipulations of HG/T 21574.
c) The inertial force on the connection between the tank body and the transport support
or lifting lug is equal to the support reaction force of the transport support of lifting
lug.
6.3.5 The effects of wind load, seismic load and snow load shall be considered for the dynamic
load.
6.3.6 For vertical cryogenic vessels, the load on the annular space supporting component and
the support reaction force of the outer shell at the support when the tank body is in the horizontal
state during the manufacturing, transportation and hoisting conditions shall be considered.
6.4 Exemption Criteria for Fatigue Analysis
6.4.1 When all the requirements of 6.4.2, 6.4.3 or 6.4.4 are satisfied, the fatigue analysis may
be exempted. Otherwise, the inner vessel shall be designed for fatigue analysis in accordance
with JB 4732.
6.4.2 For the inner vessels with number of cycles  106, if the designed cryogenic vessel has
comparable shape and load conditions to the cryogenic vessels with successful experience in
application, and has been operated for sufficient time and approved by service experience, it
can be exempted from the fatigue analysis. However, special attention shall be paid to the
adverse effects of the following situations:
a) The inner vessel adopts a non-integral structure, for example, the opening is
reinforced with a reinforcing ring or a fillet welded joint;
b) There are significant thickness variations between adjacent parts of the inner vessel;
c) Adapting pieces and adapter pipes located in the transition zone of the molding head.
6.4.3 When the inner vessel is made of austenitic stainless steel, the sum of the following
various cycles does not exceed 4,000 times:
a) The estimated (design) number of cycles of the full range of pressure cycles, including
filling and liquid discharge;
b) The estimated (design) number of cycles of the working pressure cycles where the
pressure fluctuation range of the inner vessel exceeds 50% of the design pressure;
c) For the effective number of fluctuations in metal temperature difference between any
two adjacent points, including the piping, the calculation method of the effective
number shall comply with the relevant stipulations of JB 4732;
d) For the components (including welds) composed of materials with different
coefficients of thermal expansion, the number of temperature fluctuation cycles when
(1  2) T > 0.00034, in which, 1 and 2 are the respective average coefficient of
thermal expansion of the two materials, T is the temperature fluctuation range during
operation.
6.4.4 Satisfy the corresponding fatigue analysis exemption conditions specified in JB 4732.
7 Temperature
7.1 Design Temperature
7.1.1 The design temperature of the inner vessel shall not be lower than the possible maximum
working temperature of the metal of the elements under normal working conditions.
7.1.2 The design temperature of the outer shell shall consider the influence of ambient
temperature and service conditions, and shall not be lower than 50 C.
7.1.3 When verifying the stability of each element, its design temperature shall consider the
maximum temperature that may occur under normal working conditions and when the tank
body is heated and vacuumed.
7.2 Minimum Design Metal Temperature
7.2.1 The minimum design metal temperature of the inner vessel shall consider the influence of
the minimum working temperature of the medium on the metal temperature of the inner vessel
under normal working conditions, and under inspection and test conditions, and shall not be
higher than the boiling point of the medium.
7.2.2 The minimum design metal temperature of the outer shell shall consider the influence of
the low temperature of the atmospheric environment at the location of use and the service
conditions (for example, the vaporizer hanging on the outer shell) on the metal temperature of
the tank shell, and shall not be higher than 20 C.
8 Pressure
8.1 Design Pressure
8.1.1 The design pressure of the inner vessel shall be determined in accordance with the
following requirements:
a) The internal pressure shall not be less than the working pressure of the filling and
liquid discharge conditions, and shall not be less than the saturated vapor pressure
(gauge pressure) of the medium at the design temperature;
b) The external pressure shall not be less than the maximum internal and external
pressure difference that may occur during the manufacture, transportation, filling,
liquid discharge, inspection and testing, or other working conditions of the cryogenic
a) For materials with a specific yield point, the allowable stress is not greater than the
yield strength of the material at the standard room temperature divided by 1.5;
b) For materials without a specific yield point, the allowable stress is not greater than
0.2% of the specified plastic elongation strength of the material at the standard room
temperature divided by 1.5;
c) For non-metallic materials (pipes, rods or plates), for example, epoxy glass fiber
reinforced plastic for low-temperature use, the allowable stress values for bending,
compression and shearing shall be the bending, compression and shearing strength
values in the corresponding directions at room temperature specified by the
corresponding product standards divided by the safety factor, which is not less than 4.
The test methods for bending, compression and shearing of the specimens shall
respectively comply with the stipulation of GB/T 9341, GB/T 1448 and GB/T 1450.1.
10.5 When the seismic load or wind load is combined with other loads in 6.2, the allowable
design stress of the stress-bearing elements and load-bearing components of the tank body shall
not exceed 1.2 times the allowable stress; the combination requirements shall comply with the
corresponding standards.
10.6 The allowable stress of the bolt material at different temperatures shall be selected in
accordance with the stipulations of GB/T 150.2 and the corresponding standards.
11 Corrosion Allowance
11.1 The corrosion allowance of the cryogenic vessel shall be determined by the designer in
accordance with the conditions provided by the design entrusting party.
11.2 For elements with uniform corrosion or wear, the corrosion allowance shall be determined
in accordance with the expected design service life of the cryogenic vessel and the corrosion
rate (and wear rate) of the medium to the material. When the inner vessel is made of austenitic
stainless steel, uniform corrosion is generally not considered.
11.3 When the corrosion degree of each element of the tank body is different, different corrosion
allowances may be adopted.
11.4 Corrosion on the inner surface of carbon steel or low alloy steel shell is generally not
considered. When there are reliable anti-corrosion measures on the outer surface of the shell,
the corrosion allowance may not be considered; when there is no reliable anti-corrosion
measure on the outer surface of the shell, the corrosion allowance shall not be less than 1 mm.
12 Thickness of Tank Body
12.1 The determination of the minimum thickness of the tank body shall consider the influence
of factors, such as: manufacture, transportation and installation. After the inner vessel and the
shell body of the outer shell are processed and formed, the minimum thickness, excluding the
corrosion allowance, shall comply with the following requirements:
a) For carbon steel and low-alloy steel shell, it shall not be less than 3 mm;
b) For the inner vessel and outer shell of austenitic stainless steel, it shall not be less than
2 mm.
12.2 The design thickness of the tank body shall not be less than the greater value of the
following values:
a) The sum of the calculated thickness and the corrosion allowance;
b) The sum of the minimum thickness of the tank body and the corrosion allowance
determined in accordance with 12.1
13 Filling Rate
13.1 The maximum filling rate shall comply with the following stipulations:
a) For cryogenic vessels filled with non-flammable and explosive media, the maximum
filling rate that may be achieved under any circumstance shall not be greater than 98%;
b) For cryogenic vessels filled with flammable and explosive media, the maximum
filling rate that may be achieved under any circumstance shall not be greater than 95%.
13.2 The specified filling rate shall comply with the following stipulations:
a) For cryogenic vessels filled with non-flammable and explosive media, the specified
filling rate shall not be greater than 95%;
b) For cryogenic vessels filled with flammable and explosive media, the specified filling
rate shall not be greater than 90%.
13.3 When determining the initial filling rate, factors like the expected holding time (including
the situation that the liquid may not be used for a long time) and the maximum filling rate for
the storage of the refrigerated liquefied gas in the cryogenic vessel; the initial filling rate shall
not exceed the specified filling rate.
13.4 The cryogenic vessels shall be provided with an overflow port. One or multiple overflow
ports shall be set up in accordance with the designed service conditions, and shall comply with
the stipulations of 13.3.
14 Vacuum Insulation Performance Indicators
14.1 The static evaporation rate of the cryogenic vessel for the commonly seen refrigerated
line of the opening shall be along the normal direction of the head. The cover of the process
manhole should be a formed head, and the connection between the head and the cylinder of the
process manhole shall adopt a welded structure.
18.1.7 The opening reinforcement of the inner vessel should adopt an integral reinforcement
structure.
18.1.8 The annular space piping should be set at the fixed end of the inner vessel.
18.1.9 When the hydraulic pressure test method is adopted for the inner vessel, a water drainage
outlet shall be provided, so that the accumulated water can be drained out after the test.
18.1.10 The design of the tank structure for the storage of liquid oxygen shall consider avoiding
the accumulation of hydrocarbons.
18.1.11 When the outer shell of the tank body has a suspended self-pressure booster or vaporizer,
the influence of the external low-temperature airflow environment of the self-pressure booster
or vaporizer on the outer shell material shall be considered.
18.2 Welded Structure
18.2.1 The structure of the welded joint shall adopt the joint type with relatively high static load
capacity and fatigue strength as far as possible.
18.2.2 Except for the last closed circumferential weld of the inner vessel, Type-A and Type-B
welded joints shall adopt butt joints with full cross-section penetration; the closed
circumferential welds are allowed to adopt butt joints with permanent backing plate. For the
vertical cryogenic vessels, the closed circumferential welds with permanent backing plate
should be arranged at the connection between the upper head and the cylinder.
18.2.3 In addition to the closed circumferential weld that is finally assembled to form the closed
outer shell, Type-A and Type-B welded joints shall also adopt full penetration butt joints. Closed
circumferential welds are allowed to have single-sided welded butt joints with permanent
backing plate.
18.2.4 The pipes in the annular space shall be connected to the inner vessel shell through the
pipe base. The pipe butt joints and the butt joints between the pipes and the pipe base should
adopt butt welded joints with equal wall thickness.
18.2.5 Type-D joint connecting the pipe base and the inner vessel shell shall adopt the full cross-
section penetration welded joint shown in Figure D.4 in GB/T 150.3-2011.
18.2.6 When the thickness of the steel plates on both sides of Type-B welded joints on the shell
is not equal, the edges shall be chamfered in accordance with the requirements of GB/T 150.4.
Excessive concentration of welds on the shell shall be avoided, so as to reduce shell deformation
and stress concentration at the welded joints.
18.2.7 When two different materials are welded, the type of welded joint shall consider factors
......
 
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