Some standard content:
Industry Standard of the People's Republic of China
International General Design System and Method
HG/T 20570-95
Process System Engineering Design
Technical Regulations
1996-05-02 Issued
1996-09-01
Ministry of Chemical Industry of the People's Republic of China
Industry Standard of the People's Republic of China
Technical Regulations for Process System Engineering Design
HG/T 20570-95
Editor: Process System Design Technology Center of the Ministry of Chemical Industry Approved by the Ministry of Chemical Industry
Implementation Date: September 1, 1996
Engineering Construction Standard Editing Center of the Ministry of Chemical Industry
Setting of Steam Trap
HG/T 20570. 21-95
General preparation position: China National Chemical Engineering Corporation Approval department: Ministry of Chemical Industry
Implementation date: September 1996-
Compiler
Huang Xin, China National Chemical Engineering Corporation
Reviewer:
China National Chemical Engineering Corporation, Yang Yi
Staff member of the Process System Design Technology Center of the Ministry of Chemical Industry
Seal drive element
Scope of application
This regulation applies to the calculation and selection of steam traps (hereinafter referred to as traps) in the design of chemical plants 1
2 Setting of traps
Traps should be set at the following locations:
2.0.1 The end or lowest point of saturated steam pipes (including steam pipes with hot water). 2.0.2 The middle of long-distance steam pipes, for steam pipes with saturated steam! 2.0.3 The dead end of the steam pipe where the steam does not flow is the lowest point, such as the valve of the steam pipe in the public material station, the steam water separator, the steam distribution tank or pipe, the low point of the steam pressure reducing humidifier and the water level control point of the flash dew. 2.0.6 Steam cooling equipment: the condensate outlet of the central sleeve and coil. 2.0. Equipment and pumps that are often in a state of standby: the lowest point of the steam inlet pipe of the equipment and foundation that are constantly in operation and the equipment and power source that are not in standby. 2.0.8 Other occasions where drainage is required.
3 The technical performance of the main device of the water valve
3.0.1 According to the action principle, the classification of the water valve is shown in Table 3.0.1. Jingshuimin Classification Table
Mechanical type
Orifice type, disc type
Bimetallic type, pattern type
Float type, bucket type
3. Core.1.1 Thermodynamic type water drain
Action principle
Night 3. (. 1
Thermodynamic and fluid dynamic characteristics of steam traps Temperature difference between steam and light condensate
Difference in flash density between steam and condensate
Small volume, light weight, low installation, rental and maintenance, low price, strong water resistance, not easy to ball: not suitable for drainage, the allowable back pressure of the valve is not less than 5C, of which the pulse type is not less than 25%, (1) Disc-type steam trap
Shrinkage intermittent drainage, making a sound, can discharge water close to saturation temperature, subcooling is G℃~8, with full capacity (about 3), active exhaust and water hammer resistance, its back pressure should not exceed 50% of the minimum input, and the minimum working pressure difference is 4=0.05MPa. The installation position is not restricted, and it can be used with frost. The outlet is installed straight down.
(2) Pulse steam trap
has a simple structure and can continuously drain water, but has a large steam leakage, and the allowable back pressure is low (more than 25). (3) Labyrinth steam trap
has a simple structure and can continuously drain water and exhaust gas. The micropore type is suitable for small displacements, and the labyrinth type is suitable for extra-large displacements. It cannot adapt to the situation where the flow rate changes greatly, and the suction method is to prevent the blockage of the flow channel. 3..1.2 Thermostatic steam trap
has less noise than other types of steam traps, and is in an open state when overflowing. When starting or stopping normal operation, the condensate accumulated in the system can be discharged in a short time, so that the steam trap will not freeze. Because the type is based on the differential pressure Action, so the operation is not sensitive, can not follow the rapid change of load. It is only used in the occasions with low pressure and small pressure change. The measured accuracy is not less than 30%. (1) Flow-type or back-expansion type hydrophobic structure is not very sensitive, can exclude water with temperature of 0~100℃, and can also exclude air. It is suitable for non-condensing water in heating pipelines with low heating temperature requirements. 565
(2): Steam-powered hydrophobic detachment
has a simple structure, flexible action, continuous drainage, good air drainage performance, subcooling 3~20℃, allowable back pressure of more than 30%, leakage record of less than 3%, not limited by the installation cover. But it has poor anti-fouling and water resistance, and can also be used as a steam system exhaust valve. || tt||(3) Bellows-type end water valve
Simple structure, sensitive action, intermittent drainage, subcooling 5-20 degrees, limited by the material of the bellows, the suction is 1.MPa (gauge), the pollution index and water hammer are poor, and it can be used as a hot steam system to help the air waist. (4) Bimetallic steam trap
High action sensitivity, continuous drainage, good water holding performance, large subcooling degree, and can be used as a steam trap. Good exhaust performance, and reverse injection has a stop function, the maximum use pressure can reach 21.5MPa (gauge) and the highest use temperature can reach 550℃. It has strong anti-fouling and anti-water hammer performance, and the maximum allowable back pressure is 50% of the inlet pressure. The back pressure can be increased by adjustment, and it can also be used as a curtain steam system potential air vibration.
(5) Double-noise adjustable steam trap (engineering) can artificially control the degree of discharge of condensed water. It uses the sensible heat of high-temperature condensed water and adopts the closing system of "automatic closing, automatic centering and automatic seating core". It has a long service life and a small size. It can be installed in any direction. It has continuous drainage and good exhaust performance. The allowable back pressure can reach 3.0.1.3, and the energy saving effect is good. 3.0.1.3 Mechanical steam trap
This type of steam trap has a small sound. The molten cobalt water is removed quickly. The appearance is larger than other types of steam traps. It is installed horizontally: suitable for large jellyfish. The allowable pressure of the valve is less than 80. (1) Free float type steam trap
Simple structure, high sensitivity, continuous drainage, small amount of fresh steam, divided into two types with automatic exhaust function and without automatic exhaust function. When the latter is selected, it is necessary to select an additional static exhaust valve or a manual exhaust valve without manual exhaust. The maximum operating pressure is H.MPu (table), the allowable back pressure is relatively large, up to 80%, the ability to resist water and scale is good, the action is slow, very regular, the performance is stable, reliable, (2) The structure of the machine rod float type water valve
is relatively complex, the sensitivity is low, the continuous seam drainage, the steam leakage is small, and it is divided into two types with automatic exhaust function and without automatic exhaust function. When the latter is selected, it is necessary to select an additional natural gas or a dynamic air valve. It can adapt to the change of load and automatically adjust the water volume, but the performance and anti-fouling ability are poor. (3) The float type double seat semi-balanced water valve (G type) is non-water-based, but it is relatively small and light compared to other types of steam traps. It is equipped with a bimetallic air exhaust and can automatically exhaust air. The float is filled with a volatile liquid, which increases the pressure resistance of the float, has a large water resistance, and can continuously drain water.
(1) To the bucket type (bell-shaped float or) steam trap, the steam leakage is 2%~3% and can discharge air. The rated operating pressure range is less than 1.6MPa (gauge). The use conditions can be automatically adapted. The allowable back pressure is 80%, but the inlet pressure difference cannot be less than .MPa. The action is slow and regular, and the performance is stable and reliable. The working pressure must be adapted to the volume and size of the float. The structure is relatively complex, and the seat and pins are easy to be damaged. It should be filled with water before use. (5) The bell-shaped float water valve adopts a mechanical rod structure to increase the opening and closing isolation force, with a large lifting capacity, a soft floating core, flexible action, long life, good steam resistance and drainage performance, automatic air discharge, and an allowable back pressure of %. Strong dirt resistance and easy maintenance. Compared with similar steam traps, it has a small volume and a large discharge port. (6) Differential pressure bell float type water trap (ER type) uses a closing system of automatic closing, automatic centering and self-sealing valve core, with long service life, flexible action, good water resistance, automatic air removal, small body stroke, large displacement and good strength compared with net type steam trap. The closing mode: small operation vibration, stable operation of main and auxiliary valves, and overcome the disadvantages of impact wear. 3.0.1.4 Other types of steam traps
There are steam traps with thermodynamic type or thermostatic type or mechanical fatigue performance or both or more, and some steam traps have functions that conventional steam traps do not have. For example: float type metal water valve, this type of steam trap has a complex structure and delicate operation. It has the functions of steam trap, filter, air, return valve, stop valve and bypass valve. It can work normally within the specified operating range. As a close-fitting type, it must be installed horizontally. 535
4.0.1 Selection of steam traps
4.0.2.1 Selection essentials
4 Selection of steam traps
(1) It can timely discharge condensate (except for those with supercooling requirements) (2) Minimize the steam leakage dam tip.
(3) It has a wide working pressure range, and the pressure change has little impact on its positive working pressure, and the allowable back pressure is large (except for those that do not collect condensate) (4)
It can automatically discharge non-condensable gases
It is sensitive in action, reliable in performance, durable, has a small resistance to water and dirt, and is easy to install and maintain.
It has small dimensions, light weight, and is affordable. (9) The parameters to be selected are as follows:
Type of steam trap (working characteristics)
Capacity of steam trap (water trap)
Maximum operating pressure of steam trap;
Maximum operating temperature of steam trap;
Inlet pressure of steam trap under normal conditions;
Outlet pressure (back pressure) of steam trap under normal working conditions: Valve body material of steam trap:
Diameter of connecting pipe of steam trap (pipe size) Connection method of inlet and outlet of steam trap. 4.0.1.2 Notes on selection bzxZ.net
(1) When selecting a steam trap, you should choose a steam trap that meets the standards of the network. This type of steam trap is prefixed with "Cm" before the valve code S. The basic service life is 8000 hours and the steam leakage rate is 3%. The steam trap performance should be based on the manufacturer's instructions or samples. (2) In a system with unstable load, if the discharge volume may be lower than 15% of the rated maximum discharge volume, pulse steam traps should not be used to avoid steam leakage under low load. (9) Once the condensate is formed, it must be immediately removed. It is not advisable to use impulse and bellows steam traps (both must have a certain degree of tolerance). Float-type ES and upper-type mechanical water valves can be used. Mesh disc steam traps can also be used:
() For steam sump, steam pipes with water distributors and steam turbine casings, float-type steam traps can be used. If necessary, thermal steam traps can be used. Water valve, pulse type and temperature type water valve cannot be selected. (5) The dynamic type water drain has the performance of close to continuous drainage: its application range is relatively large, and it can be generally selected. The maximum allowable back pressure shall not exceed the inlet pressure, and the outlet pressure difference shall not be less than .6MiPa. (8) The company's work depends on steam heating equipment or pipes, and the mechanical core type water valve can be used. () Mechanical type water valve is not used outside the cold building area, otherwise it should be connected with the brain, (8) The selection of the water drain should be combined with the installation location, Figure 4, 0.1 shows: Figure 4., 1) is an optional plastic type water drain Figure 4. (1 (6) is not available for floating type, and a double gold water drain valve can be selected. Figure 4, 0.1 () is an optional floating type. Thermal power type and double gold test water drain (a)
Figure 4. . 1 Different installation positions of the steam trap Figure 4.0.1 (α) The steam trap installation position is lower than the heating equipment. Figure 4..1 (> The steam trap installation position is higher than the heating equipment. Figure 4.0.1 [c> The steam trap installation position elevation is basically the same as the heating equipment, (9): For steam-using equipment that is prone to steam generation, an inverted bucket steam trap or a floating ball water valve installed with a ship lock valve (a device installed in the small steam trap for forced bottom exhaust> can be used. (10) Pipe heat pipes, steam jacket heating pipes, various heat exchangers, radiators and some steam equipment that needs to be selected according to the operating requirements to discharge the cold water can be selected. The cover adjustment type and other thermal static type water regulation requirements are the same as the steam equipment constant temperature optional additional source adjustment plastic water dew, 4. (.2 The specification of the steam trap is determined by the number of || tt| |4.0.2.1 Determination of drainage volume
(1) Condensate
For steam equipment in continuous operation, the condensate volume (G.) should be calculated based on the maximum continuous steam volume calculated by the process. For steam equipment in intermittent operation, (G) should be calculated based on the maximum steam volume in the operation cycle. When the steam volume during operation is greater than the above value, the following clause (2) can be used to increase the safety factor according to the specific situation. The condensate can be discharged through the blowdown valve or a water pump can be connected in parallel: The drainage volume of steam pipes and steam heat pipes can be the calculated value of the condensate generated during normal operation. If the condensate generated during operation is greater than the calculated value, the condensate generated during operation can be discharged through the blowdown valve. The condensate generated during operation can be discharged through the steam pipe reverse valve. C.+ 4 x60
G——Condensed water volume of the pipe, g/h;
Total weight of steel pipes and valves, kg:
Weight of insulation materials for aluminum pipes and valves·kg+Specific heat of radiator kJ/kz·
Compensation steel C1-0.469
Alloy steel C10.486
C——Specific heat of insulation material, kJ/kg·t or take Ca=0.837
Heating rate of pipe, ./min
-generally take t,=5 r:/min
——Heating rate of insulation material, C/min, generally take 4t,-
The temperature of superheated steam or the temperature of steam under the lower working conditions+kJ/kg;——Melting temperature of saturated water under the upper working conditions, k/kg. &, The amount of condensed water in the steam pipe during normal operation: G
Q Steam pipe heat dissipation unit, kJ/h:
Gea: ,,2 Same as formula (1.0.2-1).
In. Table 4.0.2-1 is the empirical value of the steam volume used in the steam companion pipe 538
(4.0.2-1)
. 0.2-231[c> The installation position elevation of the steam trap is basically the same as that of the heating equipment. (9): For steam-using equipment that is prone to steam generation, an inverted bucket trap or a floating ball trap installed with a lock valve (a device installed in the trap for forced bottom exhaust) can be used. (10) For pipe fittings, heat pipes, steam jacket heating pipes, various heat exchangers, radiators, and some steam equipment that requires constant temperature of steam equipment, the temperature of the steam trap can be adjusted according to the operating requirements. The temperature of the steam trap can be adjusted according to the requirements of the operation requirements. 4.(.2 Specifications of the trap
4.0.2.1 Determination of the discharge volume
(1) Condensate|| tt||For steam equipment in continuous operation, the condensate volume (G.) should be calculated based on the maximum continuous steam volume calculated by the process. For steam equipment in intermittent operation, (G) should be calculated based on the maximum steam volume in the operation cycle. When the steam volume during operation is greater than the above value, the safety factor can be increased according to the specific situation. The following clause (2) can be used to discharge the condensate through the blowdown valve, or a water pump can be connected in parallel: The water discharge volume of the steam pipe and steam heat pipe can be the calculated value of the condensate generated during normal operation. If the condensate generated during operation is greater than the calculated value, the condensate generated during operation can be discharged through the blowdown valve. The condensate generated during operation can be discharged through the steam pipe reverse valve. C.+ 4 x60
G——Condensate volume of pipe, g/h;
Total weight of steel pipe and valve, kg:
Weight of insulation material for aluminum pipe and valve·kg+Specific heat of pipe kJ/kz·
Compensation steel C1-0.469
Alloy steel C10.486
C——Specific heat of insulation material, kJ/kg·t or take Ca=0.837
Temperature speed of pipe, ./min
-Generally take t,=5 r:/min
——Heating rate of insulation material, C/min is generally taken as 4t,-
The melting point of natural steam or steam under the lower working conditions, kJ/kg; ——The melting point of saturated water under the upper working conditions, k/kg. &, The amount of condensed water in the steam pipe during normal operation: G
QThe heat dissipation unit of the steam pipe, kJ/h:
Gea: ,,2 Same as formula (1. 0. 2-1).
In. Table 4.0.2-1 is the empirical value of the steam volume used by the steam companion pipe 538
(4. 0. 2-1)
. 0.2-231[c> The installation position elevation of the steam trap is basically the same as that of the heating equipment. (9): For steam-using equipment that is prone to steam generation, an inverted bucket trap or a floating ball trap installed with a lock valve (a device installed in the trap for forced bottom exhaust) can be used. (10) For pipe fittings, heat pipes, steam jacket heating pipes, various heat exchangers, radiators, and some steam equipment that requires constant temperature of steam equipment, the temperature of the steam trap can be adjusted according to the operating requirements. The temperature of the steam trap can be adjusted according to the requirements of the operation requirements. 4.(.2 Specifications of the trap
4.0.2.1 Determination of the discharge volume
(1) Condensate|| tt||For steam equipment in continuous operation, the condensate volume (G.) should be calculated based on the maximum continuous steam volume calculated by the process. For steam equipment in intermittent operation, (G) should be calculated based on the maximum steam volume in the operation cycle. When the steam volume during operation is greater than the above value, the safety factor can be increased according to the specific situation. The following clause (2) can be used to discharge the condensate through the blowdown valve, or a water pump can be connected in parallel: The water discharge volume of the steam pipe and steam heat pipe can be the calculated value of the condensate generated during normal operation. If the condensate generated during operation is greater than the calculated value, the condensate generated during operation can be discharged through the blowdown valve. The condensate generated during operation can be discharged through the steam pipe reverse valve. C.+ 4 x60
G——Condensate volume of pipe, g/h;
Total weight of steel pipe and valve, kg:
Weight of insulation material for aluminum pipe and valve·kg+Specific heat of pipe kJ/kz·
Compensation steel C1-0.469
Alloy steel C10.486
C——Specific heat of insulation material, kJ/kg·t or take Ca=0.837
Temperature speed of pipe, ./min
-Generally take t,=5 r:/min
——Heating rate of insulation material, C/min is generally taken as 4t,-
The melting point of natural steam or steam under the lower working conditions, kJ/kg; ——The melting point of saturated water under the upper working conditions, k/kg. &, The amount of condensed water in the steam pipe during normal operation: G
QThe heat dissipation unit of the steam pipe, kJ/h:
Gea: ,,2 Same as formula (1. 0. 2-1).
In. Table 4.0.2-1 is the empirical value of the steam volume used by the steam companion pipe 538
(4. 0. 2-1)
. 0.2-23
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