Cooling Water Test Unit Incorporating Heat Transfer Surfaces
|Publication Date:||1 March 1986|
Cooling tower water systems are critical elements in the operation of most process plants. Recirculation of the water used in cooling tower systems reduces fresh-water requirements and makes it economically feasible to adjust the water composition in order to control corrosion and fouling rates. The effectiveness of corrosion and fouling control programs in cooling water systems can be monitored by test heat exchangers mounted in a bypass. Conditions on heat transfer surfaces can then be determined at any time, without removing plant equipment from service.
The test unit described in this standard should be used whenever cooling tower systems are critical to the process. Data from the test unit can be used to:
(a) predict service life of heat exchangers,
(b) predict heat transfer coefficients,
(c) determine fouling rate,
(d) determine relative performance of various treatment programs,
(e) optimize costs of treatment programs,
(f) minimize unplanned shutdowns resulting from fouling or corrosion, and
(g) determine effect of alloy selection on fouling and corrosion rates.
This standard considers tube-side water only. It is recognized that many exchangers have shell-side water; however, proper modeling of shell-side conditions is much more complex.
This standard covers test exchangers heated by highpurity steam only. Other heating fluids (hot water, process fluids, etc.) may be used, provided they are noncorrosive and nonfouling. If the steam purity is low or variable, steps to monitor steam purity are needed. Use of a heating fluid other than saturated steam requires modification of the heat transfer calculations in Section 5.