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GB/T 16507.7-2022 PDF in English


GB/T 16507.7-2022 (GB/T16507.7-2022, GBT 16507.7-2022, GBT16507.7-2022)
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GB/T 16507.7-2022: PDF in English (GBT 16507.7-2022)

GB/T 16507.7-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.060.30
CCS J 98
Replacing GB/T 16507.7-2013
Water-tube boilers - Part 7: Safety appurtenances and
instruments
ISSUED ON: MARCH 09, 2022
IMPLEMENTED ON: OCTOBER 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 6
1 Scope ... 8
2 Normative references ... 8
3 Terms and definitions ... 9
4 Basic requirements ... 10
5 Safety valve ... 10
6 Pressure measuring device ... 19
7 Water level measurement and display control device ... 21
8 Temperature measuring device ... 23
9 Blowdown and water emission device ... 24
10 Alarm and protection devices ... 25
11 Other appurtenances ... 35
Bibliography ... 37
Water-tube boilers - Part 7: Safety appurtenances and
instruments
1 Scope
This document specifies the requirements for safety appurtenances and instruments of
water-tube boilers, including safety valves, pressure measuring devices, water (liquid)
level measurement and display control devices, temperature measuring devices,
blowdown emission and water emission devices, and protection devices.
This document is applicable to the safety appurtenances and instruments selected for
water-tube boilers defined in GB/T 16507.1.
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 amendments) applies.
GB/T 1239.2, Cold coiled helical springs technical specifications - Part 2:
Compressions spring
GB/T 12228, General purpose industrial valves - Specification of carbon steel
forgings
GB/T 12229, General purpose industrial valves - Specification of spheroidal
graphite iron castings
GB/T 12230, General purpose industrial valves - Specification of stainless steel
castings
GB/T 12241, Safety valves - General requirements
GB/T 12242, Pressure relief devices - Performance test code
GB/T 16507.1, Water-tube boilers - Part 1: General requirements
GB/T 16507.2, Water-tube boilers - Part 2: Materials
GB/T 16507.4, Water-tube boilers - Part 4: Strength calculation of pressure parts
GB/T 20438 (all parts), Functional safety of electrical/electronic/programmable
electronic safety-related systems
GB/T 21109 (all parts), Functional safety of safety instrumented systems in the
process industry sector
GB/T 23934, Hot formed helical compression springs - Technical Requirement
GB 50116, Code for design of automatic fire alarm system
GB 50229, Standard for design of fire protection for fossil fuel power plants and
substations
DL/T 5428, Technical code for design of IC protection system in fossil fuel power
plant
NB/T 47063, Safety valves for power station
3 Terms and definitions
The following terms and definitions defined in GB/T 16507.1 apply to this document.
3.1 instrument
A device used alone or in combination with other equipment to make measurements.
3.2 quencher
The equipment that uses air or water to cool the slag emission at the bottom of the
circulating fluidized bed boiler.
3.3 bed temperature
The temperature of the gas-solid two-phase flow in the dense phase zone of the
circulating fluidized bed boiler.
3.4 bed pressure
The pressure difference obtained by subtracting the resistance of the air distribution
plate from the pressure difference between the lower air chamber of the circulating
fluidized bed boiler air distribution plate and the furnace outlet.
3.5 safety valve
Valves that protect pipelines or equipment.
NOTE: When the medium pressure in the pipeline or equipment exceeds the specified value, the
opening-closing parts (disc) will automatically open to emission the medium. When it is lower than
the specified value, the opening-closing parts (disc) will automatically close.
3.6 relief valve
An automatic pressure relief device.
NOTE: Its action is controlled by the static pressure on the inlet side of the valve. Its opening
increases with the increase of the opening pressure. It is mainly used for incompressible media.
3.7 power operated pressure relief valve
A valve whose opening or closing action is controlled entirely by a power source
(electric, pneumatic, hydraulic or pulse).
NOTE: It is a kind of controlled safety valve.
3.8 set pressure of safety valve
The set pressure at which a safety valve begins to open under operating conditions.
4 Basic requirements
4.1 The safety appurtenances and instruments configured by the boiler shall meet the
requirements for safe and reliable operation of the boiler.
4.2 The safety appurtenances and instruments configured by the boiler shall meet the
requirements of product standards.
4.3 The calibration and maintenance of measuring instruments shall comply with the
regulations of the national metrology department.
4.4 The pressure, water level and temperature measuring devices configured by the
boiler shall be installed in all necessary places. They shall be properly ranged and
reliable. The measurement value shall have enough precision.
5 Safety valve
5.1 Number and type of safety valve
5.1.1 Each boiler is equipped with at least two safety valves (including drum and
superheater safety valves). Only one safety valve may be installed if one of the
following requirements is met:
a) Steam boilers with rated evaporation not greater than 0.5t/h;
b) Steam boilers with rated evaporation less than 2t/h and equipped with reliable
overpressure interlock protection device;
such that when all the safety valves on the boiler are fully opened, the pressure inside
the boiler shall not exceed 1.1 times the calculated pressure.
5.2.3 The proportion of the emission of the superheater outlet safety valve to the total
emission shall ensure that the superheater can be cooled sufficiently when the safety
valve is opened.
5.2.4 For hot water boilers whose rated outlet water temperature is not less than 100°C,
the maximum steam production (Ev) of the boiler at the rated thermal power shall be
determined according to the formula (1):
Where,
Ev - the maximum steam output of the boiler at rated thermal power, in kilograms per
hour (kg/h);
Q - the rated thermal power of the boiler, in megawatts (MW);
Δi - the enthalpy increase, in kilojoules per kilogram (kJ/kg), which is equal to the
difference between saturated steam enthalpy and feedwater enthalpy at rated pressure.
5.2.5 The total emission of the reheater safety valve shall be greater than the maximum
design steam flow of the reheater. The emission of the safety valve at the outlet shall
ensure that the reheater can be cooled sufficiently when the safety valve is fully opened.
5.2.6 The total emission of the safety valve of the external start-up (steam-water)
separator of the DC steam boiler shall be greater than the steam production when the
DC steam boiler starts. The combined emission of the DC steam boiler safety valve and
power operated pressure relief valve (no valve at the inlet) shall be greater than the
maximum continuous evaporation capacity of the boiler. Among them, the proportion
of the emission of the power operated pressure relief valve shall not be greater than 30%
of the maximum continuous evaporation of the boiler. The emission of the power
operated pressure relief valve shall not be less than 10% of the maximum continuous
evaporation capacity of the boiler.
5.2.7 The safety valve manufacturer shall determine the emission coefficient of the
safety valve through tests. The test method and emission calculation shall meet the
requirements of GB/T 12241 and GB/T 12242. When the test conditions are lacking,
the emission of the safety valve can be calculated according to the provisions of 5.2.8.
5.2.8 The emission of steam boiler safety valve shall be calculated according to one of
the following methods:
a) According to the rated emission provided by the safety valve manufacturer;
appurtenances between the pressure element and the safety valve shall not be less than
the calculated cross-sectional area of the flow channel of the safety valve. The steam-
water resistance of such connecting pipes or pipe appurtenances shall not affect the
emission and normal operation of the safety valve.
5.4.5 The opening design of the pressure element shall ensure that the medium flow
between the pressure element and the safety valve is unimpeded. When two or more
safety valves need to be installed on one interface of the pressure element, the calculated
sectional area of the interface shall not be less than the sum of the sectional areas of all
safety valves connected to it.
5.4.6 Liquid relief valves are installed as low as possible below the normal liquid level.
5.4.7 The safety valve shall be installed in a place where it will not fail due to the
influence of the medium performance in the pressure element.
5.4.8 When the spring safety valve with threaded connection is used, it shall meet the
requirements of GB/T 12241. The safety valve shall be connected with a short pipe with
threads. The connection between the short pipe and the drum or header shell shall adopt
a welded structure.
5.4.9 The requirements for the exhaust pipe of the safety valve of the steam boiler are
as follows.
a) Steam boiler safety valve shall be equipped with exhaust pipe. The exhaust pipe
shall lead directly to a safe place. There is enough flow cross-sectional area to
ensure smooth exhaust. At the same time, the exhaust pipe shall be fixed. Avoid
affecting the correct action of the safety valve due to thermal expansion or exhaust
steam reaction. There shall not be any external force from the exhaust pipe
applied to the safety valve.
b) The exhaust pipes of two independent safety valves shall not be connected.
c) When the exhaust pipe is arranged in the open air and affects the normal operation
of the safety valve, a protective cover shall be installed. The installation of the
protective cover shall not hinder the normal operation and maintenance of the
safety valve.
d) If a muffler is installed on the exhaust pipe of the safety valve, its structure shall
have a sufficient flow cross-sectional area. There are suitable supports and
reliable hydrophobic devices.
e) The bottom of the exhaust pipe of the safety valve shall be equipped with a
drainpipe connected to a safe place. Valves shall not be installed on exhaust pipes
and drainpipes.
5.4.10 The safety valve of the hot water boiler shall be equipped with a drainpipe. The
drainpipe shall lead directly to a safe place. There is enough emission flow area to
ensure smooth emission. Valves shall not be installed on the drainpipe. Antifreeze
measures shall be taken.
5.5 Structure and material of safety valve
5.5.1 The design requirements for the safety valve are as follows.
a) Safety valves with threaded inlets or outlets shall have wrench turning surfaces,
so as to avoid damage to safety valve parts during normal installation.
b) The safety valve can be calibrated without disassembling the valve before or after
installation. The calibration will not damage the seal of the safety valve.
c) For safety valves with additional back pressure, a back pressure balancing
mechanism shall be set according to the size and variation of the back pressure.
d) The lowest part of the valve body from the sealing surface of the valve seat is
provided with a drain hole. For valves larger than DN65, the diameter of the drain
hole shall not be less than 9.5mm. For valves whose size is not larger than DN65,
the diameter of the drain hole shall not be less than 6.5mm.
5.5.2 The value of the safety valve flow channel diameter (d) is specified as follows:
a) Steam boiler: not less than 20mm;
b) Hot water boiler: when the rated outlet water temperature is less than 100°C, select
according to Table 5.
Table 5 -- Selection for flow channel diameter of boiler safety valve below 100℃
Rated thermal power of boiler
MW ≤1.4 >1.4~7.0 >7.0
Flow channel diameter of safety valve
mm ≥20 ≥32 ≥50
When the rated outlet water temperature is not less than 100°C, the number of safety
valves and flow channel diameters shall be calculated according to formula (4).
Where,
n - the number of safety valves, in pieces;
d - the diameter of the flow channel of the safety valve, in millimeters (mm);
flying off.
5.5.6 The control type safety valve shall have a reliable power source and power supply,
and shall meet the following requirements:
a) The shut-off valve on the impulse access conduit of the pulse safety valve is kept
fully open and sealed with lead;
b) The safety valve controlled by compressed air has a reliable air source and power
supply;
c) The hydraulically controlled safety valve has a reliable hydraulic transmission
system and power supply;
d) The solenoid-controlled safety valve has a reliable power supply.
5.5.7 The material of the safety valve shall meet the following requirements:
a) Valve parts materials are selected according to the provisions of GB/T 16507.2,
GB/T 12228, GB/T 12229 and GB/T 12230;
b) The corrosion resistance of the base material of the valve seat and disc is not lower
than that of the valve body material;
c) The material of the adjusting ring has good wear resistance and corrosion
resistance;
d) The spring material is selected according to the provisions of GB/T 1239.2 and
GB/T 23934.
6 Pressure measuring device
6.1 Each boiler shall be equipped with pressure gauges at the following locations:
a) in the steam space of the steam boiler drum;
b) in front of the water supply regulating valve;
c) at the economizer outlet (except drum boiler);
d) between the superheater outlet and the main steam valve;
e) at the inlet, outlet of the reheater;
f) on the start-up (steam-water) separator of the DC steam boiler or its outlet pipe;
g) at the DC steam boiler economizer inlet, water storage tank and circulation pump
outlet;
h) in front of the shut-off valve at the outlet of the evaporating heating surface of the
DC steam boiler (if a shut-off valve is installed);
i) on the drum of the hot water boiler;
j) at the outlet of the water inlet valve and the inlet of the water outlet valve of the
hot water boiler;
k) at the inlet, outlet of the circulating water pump of the hot water boiler;
l) at the oil pump inlet (oil return) and outlet of the ignition oil system of oil-fired
boilers and coal-fired boilers;
m) behind the gas source inlet of the ignition gas system of gas-fired boilers and
coal-fired boilers and the pressure-regulating valve (regulator valve) of the gas
valve group;
n) at the inlet and outlet of the furnace water circulation pump of the controlled
circulating boiler.
6.2 The selected pressure gauge shall meet the following requirements.
a) For boilers with a rated working pressure of not less than 3.8MPa, the accuracy
of the pressure gauge is not less than level 1.6. The accuracy of other boiler
pressure gauges is not less than level 2.5.
b) The range of the pressure gauge is selected according to the working pressure.
Generally, it is 1.5 to 3.0 times the working pressure. It is best to choose twice the
working pressure.
c) The size of the pressure gauge dial ensures that the boiler operator can clearly see
the pressure indication value.
d) Regularly calibrate pressure gauges. Draw the red line of the working pressure on
the dial. Indicate the next calibration date. Conduct lead sealing for the pressure
gauge after calibration.
6.3 The installation of pressure gauges shall meet the following requirements:
a) It shall be installed in a position that is convenient for observation and purging.
Protect from heat, freezing and shocks;
b) The pressure gauge set in the steam space of the boiler has a water trap or other
means of cooling the steam. Pressure gauges for hot water boilers also have buffer
elbows. The inner diameter of the elbow is not less than 10mm;
c) A three-way valve is installed between the pressure gauge and the water trap, so
as to flush the pipeline, remove or calibrate the pressure gauge.
c) Electric heating boilers.
7.1.2 The drum of each pressure level of waste heat boiler with multiple pressure levels
shall be equipped with two independent direct-reading water level gauges.
7.1.3 The water storage tank and the start-up (steam-water) separator with water storage
function in the start-up system of the DC steam boiler shall be equipped with at least
one differential pressure remote water level measuring device.
7.2 Structure and device of water level gauge
7.2.1 The water level gauge shall have obvious marks indicating the highest, lowest
safe water level and normal operating water level. The upper visible edge of the water
gauge shall be at least 25mm higher than the highest safe water level. The lower visible
edge shall be at least 25mm lower than the lowest safe water level.
7.2.2 The inner diameter of the glass tube of the glass tube water level gauge shall not
be less than 8mm.
7.2.3 To prevent people from being injured when the glass plate (pipe) is damaged, the
water level gauge shall have protective devices (protective cover, quick-closing valve,
automatic locking bead, etc.). However, any protective device shall not hinder the
observation of the real water level.
7.2.4 A set of water level gauges consisting of two or more glass plates or mica sheets
shall be able to continuously indicate the water level.
7.2.5 During the operation of the boiler, it shall be possible to blow and wash the water
level gauge and replace the glass plate (tube) and mica sheet.
7.2.6 The water level gauge shall have a water emission valve for purging and a water
emission pipe connected to a safe emission location.
7.2.7 The flow diameter of the valve between the water level meter (or water meter
column) and the drum shall not be less than 8mm. The inner diameter of the steam-
water connecting pipe shall not be less than 18mm. Connecting pipe is as short as
possible. When the connecting pipe is longer than 500mm or has a curved part, the inner
diameter shall be appropriately enlarged, so as to ensure the sensitivity and accuracy of
the water level gauge.
7.2.8 When the connecting pipe is not arranged horizontally, the condensed water in the
steam connecting pipe shall be able to flow to the water level gauge by itself. The water
in the water connecting pipe shall be able to flow to the drum by itself, so as to prevent
the formation of a false water level.
7.2.9 Valves shall be installed on the steam-water connecting pipe between the water
level gauge (or water meter column) and the drum. When the boiler is running, the valve
shall be in the fully open position. For boilers with rated evaporation less than 0.5t/h,
valves may not be installed on the steam-water connecting pipe between the water level
gauge and the drum.
7.3 Installation of water level gauge
7.3.1 The water level gauge shall be installed in a place that is convenient for
observation and operation. If the water level gauge is higher than 6000mm from the
operating plane of the boiler, a remote water level measuring device or a water level
video monitoring system shall be installed. When using a remote water level measuring
device to monitor the boiler water level, the signals shall be taken out independently.
At least two reliable remote water level measurement devices are in the boiler control
room. At the same time, a direct-reading water level gauge shall be guaranteed to work
normally during operation.
7.3.2 The installation position of the water connection pipe of the water level gauge
shall be able to correctly reflect the real water level of the drum.
7.3.3 To make the water level indicated by the water level gauge reflect the real water
level of the drum as accurately as possible, the steam-water connecting pipe and other
related components shall be well insulated.
7.3.4 When installing the boiler water level gauge with subcritical pressure and below,
the measurement error caused by the difference in density between the water level
gauge and the liquid in the boiler drum shall be corrected.
8 Temperature measuring device
8.1 Temperature measuring points shall be installed at the corresponding parts of the
boiler to measure the following temperatures:
a) Feed water temperature of steam boiler (except normal temperature feed water);
b) Water temperature at the outlet of cast iron economizer and utility boiler
economizer;
c) Water temperature at the inlet and outlet of the hot water boiler;
d) Steam temperature at the superheater outlet and each stage outlet of the multi-
stage superheater;
e) Steam temperature before and after the desuperheater;
f) Steam temperature at the inlet and outlet of the reheater and the outlet of each
stage of the multi-stage reheater (if the structure meets the installation
requirements);
g) Temperature of the upper and lower walls of the drum of the boiler with a rated
more than two boilers.
9.6 Boiler blowdown valves and blowdown pipes shall not be threaded.
9.7 Blowdown and water emission pipeline design requirements are as follows.
a) The strength calculation of the pipeline shall meet the requirements of GB/T
16507.4. Pipe appurtenances shall be selected according to the medium
parameters.
b) The corresponding pressure of the pipeline shall be determined according to the
working pressure of the boiler. In any case, the calculated pressure of the pipeline
shall not be less than 0.6MPa.
c) For boilers with a rated power above 100MW or a boiler with a rated pressure
above 9.8MPa, it is advisable to carry out stress analysis on the piping system.
10 Alarm and protection devices
10.1 The alarm shall include the following:
a) Deviation of process system parameters from the normal operating range;
b) Protection action and failure of main auxiliary equipment;
c) Monitoring system failure;
d) Failure of power supply air source;
e) Failure of electrical equipment;
f) Anomalies in the fire detection area;
g) Leakage of toxic and harmful gases.
10.2 Alarms can be divided into control system alarms and conventional light plate
alarms. The alarm shall have functions such as automatic flash, sound and manual
confirmation.
10.3 The alarm shall be completed by the alarm function of the control system. The unit
shall not only be equipped with a conventional light plate alarm device. When necessary,
no more than 20 light plate alarm windows can be set according to the following items:
a) Deviation of important parameters from normal values;
b) Unit protection trip;
c) Critical device power failure.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.