Case study pump specification

Case Study — Bleaching-Column Feed Pump Specification... 

Stringent regulatory requirements in the United States often require the incorporation of fish protection facilities at power plant intakes. There are three different concepts that can be used fish collection and removal, fish diversion, and fish deterrance. The incorporation of fish protection systems at specific sites can necessitate modifications to conventional intake designs. Such modifications can influence screen-well layouts and selection of screens and pumps, and in certain cases require model studies to develop design criteria which will ensure that fish protection facilities will be biologically effective and not adversely affect plant operations. 9 refs, cited. 

In many cases, the extraction process includes an additional, static extraction step. To this end, the outlet valve (OV in Fig. 6.10) is supplemented by an inlet valve (IV in Fig. 6.10) between the high-pressure pump and the extractor. Once the system has been pressurized, the inlet valve is closed, the high-pressure pump stopped and the oven temperature raised. After the desired temperature is reached, the system is maintained under a static regime with both valves closed, and then the valves are opened and the pump restarted to allow the solvent to flow over the dynamic extraction period. Several studies [147,150,153] have shown that a combination of both extraction modes can result in substantially improved extraction and shorter extraction times. This is commented on in greater detail in discussing specific applications below. 

The most commonly used method to measure the concentrations of corrosive gases in field environments is to adsorb the gases on chemicaUy treated filter paper, sometimes followed by a water extraction or chemical treatment, and then to determine the composition and quantity spectroscopically. IBM [75] developed a stacked canister sampler that was adapted for use in the BatteUe studies [79]. Each element in the canister stack collects a specific poUutant. The canisters are easily deployed anywhere in the world, the only inconvenience being that an air pump is required to draw a well-controlled air volume. The reliability of these pumps, based on the author s experience, is less than desirable but adequate. A similar technique, developed largely under the sponsorship of the U.S. EPA, is the "denuder tube. This method is also based on species-specific absorption of pollutants on a chemically treated surface, but in this case a permanent honeycomb substrate is mounted inside a tube. For field sampling, the tubes are stacked, the number depending on the number of species to be analyzed. Airflow pumps are also required in this approach. While this method is more cumbersome than the IBM/Battelle canisters, all the equipment and follow-up chemical analysis can be obtained commercially. 

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