Hydraulic plants

Hydraulic power systems include both hydroelectric and pumped storage hydroelectric plants. In both cases, water is directed from a dam through a series of tapering pipes to rotate turbines and create electricity. In principle, the potential energy held in the dam converts into kinetic energy when it flows through the pipes (Fig. 3.23). 

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The hydraulic system consists of oil reservoir, electric motor, hydraulic pump, heat exchange for oil cooling, oil filters, oil level indicator, electric valves and flow distributors. An hydraulic plant which has been properly installed and care has been taken during the start-up phase, should enjoy long life and not need much maintenance. 

Warner, E.H. (1905). The hydraulic plant of the Puget Sound Power Company. Trans. ASCE 55 228-261. 

In 1994, the total electrical production in France was 454 TWi, out of which 341.8 TWh (75 %) were produced by nuclear power plants, 32.2 TWh (7 %) were produced by conventional thermal plants, 80 TWh (18 %) were produced by hydraulic plants. 

The PRA model is driven by a blend of stochastic events, physical phenomena, thermal hydraulics, plant operating procedures, technical specifications, HRA, and DID principles. 

Example 1 A small simulation workflow executable in the batch mode is depicted in Fig. 10.3 (right). It consists of two simulation modules. The first module hydraulic plant simulates behavior of a hydraulic system (Fig. 10.3, left). It has one input (a pump speed) and two outputs discharge pressure and tank level). The second simulation module evaluates the quality of the simulation. It has two inputs measured tank level and expected tank level) and one performance index as output quality). All inputs and outputs are represented by time series, except for the quality output which is of the variable type single . 

Typical pilot-plant top-suspended baskets are 305 mm (12 in) diameter by 127 mm (5 in) deep. Commercial machines are available in sizes from 508-mm (20-in) diameter by 305-mm (l2-in) depth to 1524-mm (60-in) diameter by 1016-mm (40-in) depth and develop up to 1800g in the smaller and intermediate sizes. Except in the sugar apphcation, operation with a two-speed motor (half speed for loading and full speed for purging) is typical. Hydraulic drives with variable-speed capability are commonly used in the chemical industiy To maximize the number of cycles per hour, a combination of electrical and mechanical braking is employed to minimize the deceleration period, which is a transition period of no value to the process. 

Modules Eveiy module design used in other membrane operations has been tried in peivaporation. One unique requirement is for low hydraulic resistance on the permeate side, since permeate pressure is veiy low (O.I-I Pa). The rule for near-vacuum operation is the bigger the channel, the better the transport. Another unique need is for neat input. The heat of evaporation comes from the liquid, and intermediate heating is usually necessary. Of course economy is always a factor. Plate-and-frame construc tion was the first to be used in large installations, and it continues to be quite important. Some smaller plants use spiral-wound modules, and some membranes can be made as capiUaiy bundles. The capillaiy device with the feed on... 

Development The following discussion relates specifically to the use of what could be called radial-inflow, centrifugal-pump power-recovery turbines. It does not apply to the type of unit nurtured by the hydroelecti ic industry for the 1 ge-horsepower, large-flow, low- to medium-pressure differential area of hydraulic water turbines of the Felton or Francis runner type. There seems to have been little direct transfer of design concepts between these two fields the major manufacturers in the hydroelectric field have thus far made no effort to sell to the process industries, and the physical arrangement of their units, developed from the requirements of the hydroelectric field, is not suitable to most process-plant applications. 

While working in a plant, a troubleshooter read a pressure gauge daily for several weeks and only realized it was inaccurate when one day the blower was down. The gauge still read about normal operating pressure. Had this have been a distillation unit, it could have been more serious. In distillation service, pressure is a more important variable than in many other unit operations. Relative volatility is a function of pressure. Pressure, or more accurately delta-P, is the best indication of the tower hydraulics. 

Evaluates the performance of each unit of a wastewater treatment plant based on hydraulic loadings, solid flux loadings, food/microorganism ratios, sludge age, settleability, and related parameters. 

Controls as listed for dry alum apply to hydrated lime. Hydraulic jets should operate continuously and only shut off when the feeder is taken out of service. Control of the feed rate with pH as well as pacing with the plant flow may be used with hydrated lime as well as quicklime. 

Hydraulic loading Hydraulic loading refers to the flows (MGD or m3/day) to a treatment plant or treatment process. 

Shock load The arrival at a plant of a waste which is toxic to organisms in sufficient quantity or strength to cause operating problems. Possible problems include odors and sloughing off of the growth or slime on a trickling-filter media. Organic or hydraulic overloads also can cause a shock load. 

The combinations of failures and non-failed conditions define the state of the pJani at the right branches. The damage associated with these plant damage states are calculated using thermal-hydraulic analyses to determine temperature profiles that are related to critical chemical reactions, explosions and high pressure. These end-states serve as initiators fot breaking confinement that leads to release in the plant and aquatic and atmospheric release outside ol the plant,... 

Given the damage states, the analysis flows much as shown in Figure 6.3-1, depending on the process. For a nuclear power plant, thermal-hydraulic analyses determine the spatial temperature of the damaged core, and consequently the ability of the core to retain radioactive materials. Analysis of the physical processes reveals the amounts of hazardous materials that may be released. 

Section 8.1 provided a description of a core melt. This section backs up to describe thermal-hydraulic calculations of the phenomena before, during, and after the accident, and other calculations to estimate the radioactive release from containment. In this accident physics cannot be analyzed separately from in-plant transport. 

Survey and Evaluation of System Interaction Events and Sources Nuclear 4(X) occurrences of snubber failure at U.S. nuclear power plants from event reports Hydraulic and mechanical snubbers 103. 

A review of snubber operating experience at nuclear power plants from 1980 to 1984 is given in this report. Both hydraulic and mechanical snubber types are reviewed. 

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