GB/T 50102-2003 Industrial circulating water cooling design specification (with clause explanation)
Some standard content:
National Standard of the People's Republic of China
Code for design of cooling for industrial recirculating water
Code for design of cooling for industrial recirculating waterGB/T 501022003
Editor: Northeast Electric Power Design Institute, State Power Corporation of the People's Republic of ChinaApproval department: People's Republic of China
Effective date: 2
Ministry of Construction of the People's Republic of China
Announcement of the Ministry of Construction of the People's Republic of China
No. 11
Announcement of the Ministry of Construction on the promulgation of the national standard
"Code for design of cooling for industrial recirculating water" is now the national standard, edited as G3/T50102-2003, and will be implemented from August 1, 2003. The original "Code for design of industrial circulating water" GBI102-87 is still abolished. This specification is organized by the Standardization and Norms Research Institute of the Ministry of Construction and published by China Planning and Publishing House. Ministry of Construction of the People's Republic of China. This specification is based on the requirements of the letter issued by the Standardization and Norms Research Institute of the Ministry of Construction in March 1998 (98 Jianbiaojizi No. 15 "On the approval of the national standard "Industrial Circulating Water Cooling Design Specification" to be revised comprehensively". The responsible person of China State Power Corporation, the Northeast Electric Power Design Institute of Mongolian Electric Power Company, together with relevant units, jointly revised the national standard "Industrial Circulating Water Cooling Design Specification" (GB102-87) approved and promulgated by the State Planning Commission in March 1987 with the document No. *Jingbiao 1987384. During this revision, the specification revision group conducted extensive investigations and studies, carefully summarizing the practical experience of various industrial sectors in my country in the design, construction and operation of industrial circulating water cooling facilities in recent years, and the feedback from various units in the implementation of the 1987 version of this specification for more than 10 years; it absorbed the latest scientific and technological achievements in industrial circulating water cooling at home and abroad in recent years, referred to the latest version of the specifications, and solicited opinions from relevant domestic units and experts. After repeated revisions and discussions, the State Power Corporation of China reviewed and finalized it together with relevant departments. The original text of this specification is divided into four chapters with a total of 120 articles. After revision, it is still divided into four chapters: General Provisions, Cooling Towers, Fountains and Water Surface Cooling. The number of articles has increased to 203. Article 1, and two appendices were added. The revised specification adds the thermal calculation and aerodynamic calculation of cooling towers on the basis of the original process design content of industrial circulating water cooling facilities. The commonly used calculation formulas for water surface evaporation coefficient and water surface comprehensive heat dissipation efficiency in water surface cooling calculations are added; the content of plant cooling tower and fountain structure design and process design of using bay cooling circulating water are added. Some data in the original article are modified according to the scientific research and practical results in recent years, such as the wind loss water rate of the cooling tower, the ratio of the air inlet area to the water area, and the height of the wind duct of the mechanical ventilation cooling tower. While revising the articles, the explanations of the added and modified articles are added and modified accordingly. Although some articles have not been modified, the explanations of the articles have been modified and supplemented according to the scientific research and practical results in recent years. The provisions of Section 1
2.4 "Open Cooling Tower" and Chapter 3 "Fountain" are relatively concise and easy to operate, and the articles of these chapters and sections are not explained. : The revised specification The content of the standard is more comprehensive, and each article has good operability. Each provision is technologically advanced, economically reasonable, conducive to safe production, and convenient for construction, operation and maintenance management. It can play a good guiding role in the design of industrial circulating water cooling facilities in my country.
The specific interpretation of this standard is the responsibility of the Northeast Electric Power Design Institute of the State Power Corporation. The address of the institute is No. 118 Renmin Street, Changchun City, Jilin Province, zip code 130021, telephone 04315642361.
Revised editor: Northeast Electric Power Design Institute of the State Power Corporation Dream editing unit: Northwest Electric Power Design Institute of the State Power Corporation Main drafters: Li Zhihua, Zhong Nan, Jin Xiqing 1..1 This standard applies to newly built and expanded industrial circulating water cooling facilities
1.2 The design of industrial circulating water cooling facilities meets the requirements of safe production, economic rationality, environmental protection, resource conservation, water conservation and land conservation, so as to facilitate construction, operation and maintenance.
,03 The design of industrial circulating water cooling facilities should be based on the continuous summary of production practice experience and scientific experiments, and actively develop and seriously adopt advanced technologies. 1.0.4 The type of industrial circulating water cooling facilities should be selected based on the production process requirements for the amount of circulating water, water temperature, water quality and the operation mode of the water supply system, and combined with the following factors, through technical and economic comparison to determine: 1. Local hydrological, meteorological, topographical and other natural conditions 2. The supply of materials, equipment, electricity and make-up water 3. Site layout and construction conditions:
The impact of industrial circulating water cooling facilities on the surrounding environment. Industrial circulating water cooling facilities should be close to the main water supply and drainage, and the construction of long water supply and drainage pipes and ditches should be avoided. 1.0.6 In addition to implementing this specification, the design of industrial circulating water cooling facilities should also comply with the provisions of the relevant national mandatory standards in force. 1bZxz.net
2 Cooling tower
2.1 General provisions
2.1.1 The location of the cooling tower in the general layout of the plant shall comply with Article 1.0.5 of this standard and the following provisions:
1 In cold areas, cooling towers should be arranged on the leeward side of the dominant wind direction in winter for the main buildings and open-air distribution devices in the plant area; 2 Cooling towers should be arranged on the upwind side of the dominant wind direction throughout the year for dust pollution sources such as coal storage yards;
3 Cooling towers should be away from open-air heat sources in the plant:
4 The distance between cooling towers or between cooling towers and other buildings shall not only meet the ventilation requirements of cooling towers, but also meet the fire and entertainment requirements of pipes, trenches, roads, and buildings, as well as the construction and maintenance site requirements of cooling towers and other buildings; 5 The location of the cooling tower should not hinder the expansion of industrial enterprises. 2.1.2 When the environment has restrictions on the noise of cooling towers, the following measures should be taken to reduce noise depending on the specific conditions of the project:
Mechanical ventilation cooling towers should use low-noise fan equipment; 1
The water distribution and water collection system should be improved to reduce the water spraying noise; 3
Silence facilities should be installed around the cooling tower;
The location of the cooling tower should be far away from the noise-sensitive area. The selection of the centralized or decentralized layout of the cooling tower should be determined by technical and economic comparison based on the number of workshops using circulating water, distribution location and water requirements of each workshop.
The cooling tower can be used without equipment; measures should be taken not to affect production during the maintenance of the cooling tower. 2.1.4
2.1.5 The thermal calculation of the cooling tower should adopt the flame difference method or empirical method. .2..
2.1.6 When the thermal calculation of the cooling tower is carried out by the melting difference method, it is advisable to calculate according to the following formula: 1 Countercurrent cooling tower:
花二五
K= 1 m
武中V--the volume of the water environment (m)
Q--the circulating water flow rate entering the cooling tower (kg/*)K--the coefficient of heat dissipation of evaporating water;
The heat of vaporization of water corresponding to the water temperature after cooling (kJ/kname)(2. 1. 6-1)
(2. 1 6-2)
The mass coefficient of the water filling material related to the apparent difference (kg/m·) C—.—Specific heat of circulating water (kI/kg·℃)—…The temperature entering the cooling tower (℃)
t2Water temperature after cooling (℃)
h—Specific heat of humid air (ki/kg)
—Specific heat of saturated air corresponding to the water overflow (k/k). Formula (2.1.6-1) can be solved by Simpson's approximate integral method or other methods. When using Simpson's approximate integral method to solve, the integral area of water temperature should be divided into no less than 4 equal parts. When the water temperature difference is less than 15C, the integral area of water temperature # to the globe is also divided into 2 equal parts.
2Circular cross-flow cooling tower From the annular water-sprinkling packing of the cross-flow cooling tower, a packing unit with a center angle of is cut. Water is poured from above and air enters from the circumference. The cylindrical coordinate system is used, and the origin is the intersection of the tower axis and the extension line of the top surface of the water-sprinkling material. Downward is positive and outward is not.
=e.ah--K.(hh)
Cua agi·ar
Boundary conditions are rr, h=hzo, t=t.
Wu Fei-tower radius (m
—tower air inlet radius)
(2. 1. 6-3)
q-sprinkling density (kg/m2·s);
The average mass velocity of the air inlet section (kg/m2·s);-the specific melting of the wet air entering the cooling tower (kJ/kg). h
Formula (2.1.6-3) can be solved by analytical method or differential method. 3 Rectangular cross-flow cooling tower. Cut a packing unit from the rectangular cross-flow cooling tower, water flows down from the top, and air enters from the air inlet. The air inlet is on the left. The first angle coordinate system is used, and the origin of the coordinate is the intersection of the top surface of the water-spraying packing and the air inlet. 2 is positive downward and 2 is positive along the air flow direction.
. at=g ah=K,(h\-h)
g:ax
Boundary conditions are z=0, =;-0h=hl
Equation (2.1.6-4) can be solved by analytical method or differential method. (2. 1. 6-4)
Rectangular cross-flow cooling tower can also use equation (2.1.6-3) for thermal calculation. At this time, the inner radius of the tower can be set to a very large value. 2.1.7
Other parameters in the thermal calculation of cooling towers should be calculated according to the following formulas:
hCao+X(ro +C.0)
The specific heat of dry air can be taken as 1.005kJ/kg·℃; the specific heat of water vapor can be taken as 1.846kl/kg·'℃C: - the global temperature of air (℃)
- the heat of vaporization of water at 0℃, which can be taken as 2500kJ/kg, X the moisture content of air (kg/kg).
Saturated water vapor pressure:
lgP/=2.0057173—3.142305(1—103
Wherein P\_
(2.1.7-1)
0.0024804(373.16 --- T)
(2.1. 7-2)
Saturated water vapor pressure (kPa);
Kelvin temperature (K).
Wet air density:
(0.003483Px0.001316gPvo)
Wet air density (kg/m):
Relative humidity of air,
Atmospheric pressure (Pa)
Saturated water vapor pressure at temperature (Pa). Outlet air at global temperature:
0g +(ta1)h
hz—hi
Dry bulb temperature of air entering the tower (℃)
Dry bulb temperature of air leaving the tower (℃)
Arithmetic mean of water temperature entering and leaving the cooling tower (℃) Condensation air ratio discharged from the cooling tower (k/kg) Saturated air ratio corresponding to water temperature tm (kI/kg). Air ratio of the tower leaving the tower:
h2=hrf
Difference in water temperature between entering and leaving the cooling tower (℃)
(2. 1. 7-3)
(2. 1. 7-4)
(2. 1. 7-5)
The mass ratio of dry air and circulating water entering the cooling tower (also known as the air-water ratio).
2.1.8 The heat exchange characteristics of the water-sprayed filler should adopt the measured data of the prototype tower. When there is a lack of measured data of the prototype tower, the test data of the simulated tower can be used, and the test data of the simulated tower should be corrected according to the difference between the test conditions of the simulated tower and the operating conditions of the designed cooling tower.
The ventilation resistance of the cooling tower should be calculated according to the following formula: Temperature
Where H
The total temperature of the cooling tower Or local ventilation resistance (Pa): Wm\-
-Calculation wind speed. When calculating the total resistance of the whole tower, it is the average wind speed of the water filling calculation section. When calculating the local resistance of the cooling tower, m is the calculated wind speed at that place (m/s):
Calculation air density. When calculating the total resistance of the whole tower, e is the average density of wet air entering and leaving the cooling tower. When calculating the local resistance of the cooling tower, o is the average density of wet air at that place (kg/m2):-Total resistance coefficient or local resistance coefficient of the cooling tower, 2, 1. 10
The ventilation resistance coefficient of the cooling tower should meet the following requirements: use the measured data of the prototype tower that is the same as the cooling tower being designed; use the test data of the model tower that is similar to the cooling tower being designed; when the above data are lacking, it can be calculated by empirical method. The total resistance coefficient of the countercurrent duct simple natural ventilation cooling tower should be calculated as follows: 5-++
(2. 1.10-1)
,=(1-3.47e+3.65)(85+2.516—0.206+0.00962)(2. 1. 10-2)
=6. 72+0. 654D+3. 5g+1. 43~m—60. 61e-0.36..D(2. 1. 10-3)
(2. 1. 10-4)
wherein
total resistance coefficient,
resistance coefficient from the tower air inlet to the tower throat (excluding the water resistance in the rain area),
resistance coefficient in the rain area during watering;
resistance coefficient of the packing, water eliminator and water distribution system during watering The ratio of the tower air inlet area (the annular area of the air inlet calculated according to the diameter of the upper edge of the air inlet) to the tower area at the upper edge of the air inlet 0.35ε<0.45; D—-tower inner diameter at the bottom of the water-spraying packing (m): Um
the plane of the calculated section of the water-spraying packing Average wind speed (m/s); tower outlet resistance coefficient,
tower water spraying area (m2):
F-tower outlet area (m)
2.1, 1 The cooling water load of the cooling tower should not exceed the maximum cooling water load allowed by the production process
1 According to the requirements of the production process, the daily average meteorological conditions with a frequency of 5%~10% calculated according to the wet bulb temperature frequency statistics method are adopted; 2 The meteorological data is used for the recent continuous period of not less than 5 years, and the hottest period of each year is the daily average of June and August. 3 When the product has a group of requirements for cooling requirements or the requirements are not separated, according to the actual requirements, the meteorological conditions can also be appropriately raised and lowered. 2, 12 When calculating the monthly average cooling water load of the cooling tower, the monthly average meteorological conditions of the recent continuous period of not less than 5 years should be used. , 13 Meteorological science should select the weather station data that represents the meteorological characteristics of the cooling tower. It is advisable to set up a meteorological observation station at the cooling tower location. 2, 1: 14 The water loss of the cooling tower is determined according to the evaporation, wind and sewage intake.
2.1.15 The evaporation loss of the cooling tower as a percentage of the circulating water of the cooling tower (called the evaporation loss rate) should be calculated and determined as follows: 1 When the outlet gas calculation of the cooling tower is not performed, the evaporation loss rate is calculated as follows:
,-K·AtX100%
The evaporation loss water extraction
(2. 1, 15-1)
KzF coefficient (1/℃) is adopted according to the provisions of Table 2.1.15. When the inlet air temperature (dry bulb temperature) is an intermediate value, the interpolation method can be used for calculation. Table 2.. More coefficient K
Tower air temperature (loss)
2 When calculating the wear state of the cooling tower, the formula of hot metal is as follows:
In the formula, G
(X2-X)×100%
Mass flow rate of dry air entering the cooling tower (kg/s)Moisture content of air entering the tower (kg/kg):
Xz—Moisture content of air leaving the tower (k/kg). (2.1.15-2)
2.1.1The percentage of wind-blown water loss of the cooling tower to the circulating water volume entering the cooling tower (also known as wind-blown water loss rate) should be determined according to the tower type of the cooling tower and the escaping water rate of the dehumidifier selected in the design and the water loss rate blown out from the air inlet of the tower. When the data such as the escaping rate of the dehumidifier are missing, it can be adopted according to Table 2.1.16. Capsule 2, 1, 16 Wind-blown water loss rate (%] Tower type
With dehumidifier
Without dehumidifier
Determine:
Mechanical draft cooling tower
Wind-type natural draft cooling tower
Dispersed cooling tower
1. 00-~1. 50
The amount of water lost by sewage discharge should be calculated and determined based on the requirements for the circulating water quality. The type and material of the water-spraying filler should be selected based on the following factors: tower type;
The water temperature and water quality of the circulating water;
The thermal characteristics and resistance performance of the filler:
The physical and mechanical properties, chemical properties and stability of the filler (resistance to temperature changes, flame retardancy, fire resistance, anti-aging and corrosion resistance, etc.)
The price and supply of the filler
Convenience of construction and maintenance:
The support method and structure of the filler.
2.1.19 Both mechanical ventilation cooling towers and wind-type natural ventilation cooling towers should be equipped with dehumidifiers. Dehumidifiers should be of high dehumidification efficiency, low ventilation resistance, economical and durable types. 2.1.20 The water distribution system of the cooling tower should meet the requirements of uniform water distribution, low ventilation resistance, low energy consumption and easy maintenance in the same design water density area, and should be selected according to the following regulations based on the tower type, circulating water quality and other conditions: 8
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