GB/T 50746-2012 in English

1 General provisions

1.0.1 This code is formulated to make the design of recirculation cooling water unit meet the requirements of petrochemical enterprises on the amount, temperature, pressure and quality of recirculating cooling water and the long-term safe and stable operation of heat exchange equipment, so as to achieve the purposes of environmental protection, safe production, advanced technology, economic rationality and resource saving, and facilitate construction, maintenance and operation management.

1.0.2 This code is applicable to the design of recirculation cooling water unit for constructed, renovated and extended indirect open circulating cooling water systems in petrochemical enterprises.

1.0.3 The petrochemical recirculation cooling water unit shall be such designed by drawing on advanced scientific research achievements and production practice experience at home and abroad, and actively and steadily adopting new technologies, processes, equipment and materials.

1.0.4 In addition to this code, the design of petrochemical recirculation cooling water unit shall also meet the requirements of the current relevant standards of the nation.

2 Terms and symbols

2.1 Terms

2.1.1
recirculation cooling water unit
field consisting of cooling facility, water treatment facility, water pump, pipeline and other facilities for providing recirculating cooling water

2.1.2
recirculating cooling water system
water supply system using water as a cooling medium which will be recirculated, and consisting of heat exchange equipment, cooling facility, water treatment facility, water pump, pipeline and other related facilities

2.1.3
counter-flow cooling tower
cooling tower in which water and air flow in opposite directions, i.e. water flows from top to bottom, and air from bottom to top

2.1.4
cross-flow cooling tower
cooling tower in which water and air flow in perpendicular directions, i.e. water flows from top to bottom, and air flows horizontally
2.1.5
filling
components installed in cooling tower to make water splash into water droplets or water film, so as to increase the contact area and time between water and air

2.1.6
film filling
filling enabling the water to form a continuous thin water film on the surface of the filling

2.1.7
water flow cross per unit area of filling
amount of recirculating water flowing cross per square meter of filling section per unit time

2.1.8
air/water ratio
ratio of the dry air entering the cooling tower to the mass flow of recirculating water in the cooling tower, which is generally expressed by λ

2.1.9
design meteorological parameter
meteorological parameters used in the design of recirculation cooling water unit, including atmospheric pressure, dry bulb temperature, wet bulb temperature or relative humidity

2.1.10
approach
difference between the temperature of water flowing out of the cooling tower and the wet bulb temperature of the air entering the tower

2.1.11
cooling range
difference between the temperatures of water flowing in and out of the cooling tower

1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 General design
3.1 General requirement
3.2 Design scale
3.3 Amount of makeup water
3.4 Determination of the design temperature of recirculating cooling water
3.5 Determination of the design working pressure of recirculating cooling water
3.6 Requirements for the quality of recirculating cooling water
3.7 Site selection
3.8 Arrangement in recirculation cooling water unit
4 Cooling towers
4.1 General requirement
4.2 Calculation of cooling towers
4.3 Tower structure and component design
5 Transportation of recirculating cooling water
5.1 Selection of recirculating water pump
5.2 Water pump accessories
5.3 Recirculating water pump room
5.4 Suction pool
6 Treatment of recirculating cooling water
6.1 General requirement
6.2 Corrosion inhibition and scaling inhibition
6.3 Microbe control
6.4 Side stream treatment
6.5 Storage and infusion of chemicals
6.6 Makeup water and blow down treatment
7 Instrument and control
8 Inspection and test
9 Power supply facility
10 Auxiliary buildings and structures
Explanation of wording in this code
List of quoted standards