Cooling water recirculation system

The mass flow of MESA into the neutralizer provides the primary process control signal, and the flow of caustic soda is controlled in a fixed ratio to the inlet MESA. Process heat is removed by the heat exchanger in the neutralization loop. A cooling water recirculation system is provided and is equipped to control the temperature of the cooling water supplied to the heat exchanger. 

Starting in December 1984, the 107-N spent fuel storage basin cooling water recirculation system was operated. The 107-N basin recirculation facility cleaned N Basin in a closed-loop system. Mixed wastes were routed to the 190,000-L (50,000-gal) tank, where they were neutralized and then pumped to the 1314-N LWLS (DOE-RL 1990). 

Once-through cooling water. Recirculating cooling system blowdown. Ash transport water ... 

Continuous water recirculation system, whereby cooling water picks up heat by being pumped through a process heat source or heat exchanger and then over a cooling tower, open to the air, whereupon the sensible heat gained is lost by an evaporation process. 

PERFORMING THE STUDY. A HAZOP Study focuses on specific points of a process called "study nodes," process sections, or operating steps. Depending on the experience of the study leader, the portion of a process included in a single study node can vary. In the most conservative studies, every line and vessel are considered separately. If the HAZOP study leader is experienced, he or she may elect to combine two or more lines into a single study node. For example, the cooling water chlorination system (Example Process 2) could be separated into three study nodes (chlorine supply to venturi, recirculation loop, and tower water basin), two study nodes (recirculation loop and tower water basin combined as a single study node), or one study node (the entire process). 

The function of the reactor water recirculation system (Figure 3.8) is to circulate the required coolant through the reactor core. The system consists of two loops external to the reactor vessel, each containing a pump with a directly coupled water-cooled (air-water) motor, a flow control valve, and two shutoff valves. 

Electrode holders with a closed cooling system have proven themselves very well in practice in a number of cooling designs. They work largely without any problems however it is imperative to pay extremely close attention to the cooling water quality. Water treatment and water recirculation systems are required to prevent build up in the internal cooling chamber of the electrode and reduce cooling costs. 

Besides the cones, the metal interface housing itself is also exposed to the high-temperature plasma. Therefore, it needs to be cooled by a recirculating water system, usually containing some kind of antifreeze or corrosion inhibitor or by a continuous supply of mains water. Recirculating systems are probably more widely used because the temperature of the interface can be controlled much better. There is no... 

Fig. 4. In the Solar Two Project a molten salt system shown in the scheme replaces Solar One s water/steam system. In operation, "cold" molten salt is pumped from a storage tank to a receiver on a tower. Sunlight reflected from a field of sun-tracking mirrors heats the salt in the receiver to 1050°C. The heated salt then flows down into a hot storage tank where it is pumped to a heat exchanger to produce the steam that drives a turbine. Some of the hot molten salt can also be stored to produce steam on demand at a later time. Salt cooled to 550°C in the steam generator recirculates through the system and...

Foulants enter a cooling system with makeup water, airborne contamination, process leaks, and corrosion. Most potential foulants enter with makeup water as particulate matter, such as clay, sdt, and iron oxides. Insoluble aluminum and iron hydroxides enter a system from makeup water pretreatment operations. Some well waters contain high levels of soluble ferrous iron that is later oxidized to ferric iron by dissolved oxygen in the recirculating cooling water. Because it is insoluble, the ferric iron precipitates. The steel corrosion process is also a source of ferrous iron and, consequendy, contributes to fouling. 

Removal of Particulate Matter. The amount of particulate entering a cooling system with the makeup water can be reduced by filtration and/or sedimentation processes. Particulate removal can also be accompHshed by filtration of recirculating cooling water. These methods do not remove all of the suspended matter from the cooling water. The level of fouling experienced is influenced by the effectiveness of the particular removal scheme employed, the water velocities in the process equipment, and the cycles of concentration maintained in the cooling tower. 

Many techniques have been developed to accomplish this, for example, the use of a cooled recirculating system in which the chlorine is dissolved in one part and the allyl chloride is dissolved and suspended in another (61). The streams are brought together in the main reaction zone and thence to a separator to remove water-insoluble products. Another method involves maintaining any organic phase present in the reaction zone in a highly dispersed condition (62). A continuous reactor consists of a recycle system in which make-up water and allyl chloride in a volume ratio of 10—50 1 are added... 

Specimen Location Impeiler from a recirculating pump in a cooling water system... 

Most refinery process units and equipment are manifolded into a collection unit, called the blowdown system. Blowdown systems provide for the safe handling and disposal of liquids and gases that are either automatically vented from the process units through pressure relief valves, or that are manually drawn from units. Recirculated process streams and cooling water streams are often manually purged to prevent the continued buildup of contaminants in the stream. Part or all of the contents of equipment can also be purged to the blowdown system prior to shutdown before normal or emergency shutdowns. 

Improved service water reliability by elimination of rubber expansion joints in the recirculated cooling water system and minimization of their use in the raw service water systems... 

FIGURE 4.39 Cooling water system (open recirculation). 

FIGURE 4.40 Cooling water system (closed recirculation). 

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