Cooling towers action

Qualitative results of checklist analyses vary, but generally the analysis produces the answers yes, no, not applicable, or needs more information. The checklist is included in the PrHA report to summarize the noted deficiencies. Understanding these deficiencies leads to sa fety improvement alternatives for consideration, and to identified hazards with suggested actions. I igtires 3.3,1-4 and 3.3.1-5 present checklist analyses of the Dock 8 HF Supply and the Cooling tower chlorination respectively. 

A HAZOP study is a systematic, tabular document of process deviations. The study gives the noimal operating conditions and analysis boundary conditions for each item and lists action items for further evaluation. Tables 3.34-3 and 3.3.4-4 are examples of HAZOP analysis of the Dock 8 HF Supply System and the Cooling Tower Chlorination System, respectively (for a more complete study see DOE, 1973). These example show the format for HAZOP tables. A typical HAZOP study... 

In the cooling tower the temperature of the liquid falls and the temperature and humidity of the air rise, and its action is thus similar to that of an air humidifier. The limiting temperature to which the water can be cooled is the wet-bulb temperature corresponding to the condition of the air at inlet. The enthalpy of the air stream does not remain... 

In normal operations, continuously recirculating water picks up waste heat from a refrigeration compressor or process heat exchanger, and the hot water is pumped to the top of the tower and dropped over the cooling tower. Evaporative action removes the heat from the water and adds it to the air. The hot, moist air is ejected from the fan stack, and the cooled water returns to the compressor or exchanger to pick up more heat. Figure 1.1 illustrates the cooling tower operation. 

This paper discusses the impact of wind action on natural-draft cooling towers. The structure of the wind load may be divided into a static, a quasistatic, and a resonant part. The effect of surface roughness of the shell and of wind profile on the static load is discussed. The quasistatic load may be described by the variance of the pressure fluctuations and their circumferential and meridional correlations. The high-frequency end of the pressure spectra and of the coherence functions are used for the analysis of the resonant response. It is shown that the resonant response is small even for very high towers, however, it increases linearly with wind velocity. Equivalent static loads may be defined using appropriate gust-response factors. These loads produce an approximation of the behavior of the structure and in general are accurate. 11 refs, cited. 

Approaches to the Design of Hyperbolic Cooling Towers Against the Dynamic Action of Wind and Earthquake... 

The most critical components of a cooling system —the heat exchangers— are seldom available for regular inspection. Therefore the cooling tower usually becomes the primary focus for an inspection of the cooling system, and a subsequent estimation of the degree of cleanliness and condition of internal water-wetted surfaces. Individual tower components and sections need to be regularly inspected and an overall assessment made, with an action plan for improvement if required. 

Sterilization by chemical methods. Biocidal action has been widely used for many years to control biofilm formation in closed systems, such as heat exchangers, cooling towers, and storage tanks.64, (Dexter)5... 

Other situations in which attack by H2SO4 formed through bacterial action has been reported include cooling towers (L6) and concrete floors laid on rocks containing pyrite (FeSj) (P58). 

A cooling tower is a common way to get rid of waste heat. Inside the tower, hot water is sprayed into the air while large fans draw air through the droplets. Although this process only transfers the heat to the atmosphere, it is an improvement over pumping the hot water back into streams, an action that killed organisms in the stream. 

The first two modules (FiU the Basin/Start the Water Pumps) are in the Preparation section. The modules must be carried out in the sequence shown, i.e., filling the basin of the tower must be done before any other actions are taken. It must then be followed by the starting of the main cooling water pumps on recirculation (i.e., water from the pumps flows immediately back to the cooling tower without going to any of the users). 

This tower depends upon natural draft action the same as a chimney to draw cool air in at the bottom and expel it out the top as warm moist air (Figure 9-101). The action of the tower depends upon the atmospheric temperature therefore, on a hot day the action of the tower may be less than on a cool day. These towers are relatively large, and require power for pumping the water to a point in the tower which is usually lower than for an atmospheric tower. There are no fan costs. Units have been built 310 ft high, base diameter 210 ft and a throat of 120 ft, wdening to 134 ft in diameter at the top [30]. 

An example of such a product is ioBio , marketed by Baltimore Aircoil Co. (BAC). It is proposed for small cooling systems. This system is, in effect, an in-line dispenser of prilled elemental iodine (U), with replaceable iodine canisters available. The equipment is placed in the makeup waterline to the tower, and in-line options include filters, water meters, and back-flow prevention devices. Claims made are that the biocidal action of the elemental iodine is not affected by changes in temperature, system load, or water chemistry. Also, the system is compatible with virtually all scale and corrosion inhibitors and does not contribute to the corrosion of metal surfaces. 

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