Cooling water systems design

Rubber Manufacturing Plant Cooling Water System Design Considerations... 

The closed cooling water system design temperature depends on the maximum temperature of service water intake. The closed cooling water system satisfies the plant s full power load requirements. Extra cooling capability, with all spares operating, is adequate to handle plant startup duty. 

Most of the water used industrially removes heat from production processes. It is one of the major applications for water and is a major factor in siting plants and processes. Cooling systems suffer many forms of corrosion and failure. The diversity of attack stems from wide differences in cooling water system design, temperature, flow, water chemistry, alloy composition, and operation. An almost endless variation of process stream chemistries may be involved in cooling water systems. Refinery and chemical process industries can employ hundreds of heat exchangers at a single plant, each with a different process stream chemistry [14]. 

Metal surfaces in a well-designed, well-operated cooling water system will establish an equilibrium with the environment by forming a coating of protective corrosion product. This covering effectively isolates the metal from the environment, thereby stifling additional corrosion. Any mechanical, chemical, or chemical and mechanical condition that affects the ability of the metal to form and maintain this protective coating can lead to metal deterioration. Erosion-corrosion is a classic example of a chemical and mechanical condition of this type. A typical sequence of events is ... 

Cooling Water System. A list of cooling duties will be available at this point so the cost estimate for this system can be factored or estimated based on a similar operating system. For a more definitive estimate based on initial or detailed layout, it is probably best to use a contractor or consultant skilled in these designs. If a cooling tower is involved, the groundwork will already have been set. This basis can be passed along on specification sheets provided in the Appendix to a vendor for quotes. 

The character of surface waters can change significantly and rapidly throughout the year, and any process or cooling-water system should be designed accordingly. 

Paige. P. M. Chem. Eng.. 74(14) (1967) 93. Costlier cooling towers require a new approach to water-systems design. 

Kim J-K and Smith R (2003) Automated Retrofit Design of Cooling Water Systems, AIChE J, 49 1712. 

Unless otherwise specified, cooling water systems shall be designed for the following conditions ... 

J. Water Pollut. Control Fed., V. 51, N. 11, Nov. 1979, pp. 2602-2614 A preliminary design methodology is presented for the sidestream softeners in zero-discharge cooling water systems. The methodology consists of semiempirical chemical equations which were calibrated by experiments and which are linked to the mass balances of the important chemical species. The only inputs required are the makeup water quality and certain cooling water system parameters. 20 refs, cited. 

Current environmental regulations necessitate that new concepts be used in the design of industrial cooling water systems. Equipment selection and component layout related to these regulations are discussed. Special emphasis is given to the power requirements needed for the system. The subject matter for this paper was developed from observations of rubber industry manufacturing operations. 

Costlier Cooling Towers Require a New Approach to Water-Systems Design... 

This is designed to be used at 125 to 175 ppm reserve in a cooling water system operating at high COC. 

Almost all open recirculating cooling water systems operate within a pH range of 6.5 to 9.5. Occasionally this may be as low as 6.0 or as high as 10.0. Typically, however, water treatment programs are designed to function within only a narrow pH band of 0.5 to 1.0 pH unit or less. The specific... 

A numerical example might be useful to illustrate some of the issues discussed above. The base case reactor is used with a design conversion of 80% and reactor temperature of 320 K. The diameter of the reactor is 5 m, and the jacket area is 160 m2. With a perfectly mixed circulating cooling water system, the jacket temperature is 304 K and the flowrate of makeup cooling water is 50.8 kg/s. The physical properties of the reaction liquid are... 

If a once-through cooling water system is used, the velocity through the jacket is very small (0.032 m/s), which gives such a small h = 68 J s 1 K-1 m-2 that the design is unfeasible. Reducing the jacket clearance from 0.1 to 0.01 m, which is probably too small for a 5-m-diameter vessel, gives a ha = 682 J s 1 K 1 m-2. 

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