Cooling water outlet valve, closing

Closing the cooling water outlet valve A, about three-fourths of the gate valve steam travel, increases cooling-water flow through the precondenser. Nonsense ... 

A tube has failed in one of the four condensers about once every three years. If a condenser tube fails, the affected condenser can be removed from service by closing four isolation valves (propane vapor inlet valve), liquid propane outlet valve, cooling water supply valve, and cooling water return valve). However, if a tube fails, it is essential that the operator close the two propane isolation valves before closing the two water isolation valves. Closing the two water valves first would allow pressure to build on the tube side of the condenser and rupture the tube head. 

Open the high point vent on the top of the channel head. I am assuming water is on the tube side of a horizontal shell and tube exchanger. If the exchanger is elevated by 30 or 50 ft, there may be no water pressure at this elevation. If so, temporarily close the cooling water outlet gate valve part way to push the water out of the vent. Now take the gas test meter (the one used by the operators to issue entry permits to vessels) and hold the sample probe above the water stream to test for hydrocarbons. 

The oldest, most direct method of pressure control is throttling on the cooling-water supply. This scheme is shown in Fig. 13.5. Closing the water valve to the tube side of the condenser increases the condenser outlet temperature. This makes the reflux drum hotter. The hotter liquid in the reflux drum creates a higher vapor pressure. The higher pressure in the reflux drum increases the pressure in the tower. The tower pressure is the pressure in the reflux drum, plus the pressure drop through the condenser. 

Figure 4 Typical sequential processing steps for distilled water treatment. When cooling water is not needed, water will circulate at 80°C or above. During use the cooling water valve is open and the loop outlet valve is closed. After use the loop outlet valve is kept closed and the loop drain valve opened to flush all the cooled water to drain.

The control structure shown in Figure 6.57 is installed on the flowsheet. The feed is flow-controlled. The outlet temperature is controlled by manipulating the coolant flowrate. Note that the OP signal is sent to both of the control valves on the coolant stream, opening and closing them simultaneously. The setup works in the simulations, but it is not what would be used in a real physical system. A pressure-driven simulation in Aspen Plus requires that valves be placed on both the inlet and outlet coolant streams. In a real system, the cooling water would be drawn from a supply header, which operates a fixed pressure. A single control valve would be used, either on the inlet or on the outlet, to manipulate the flowrate of coolant. 

In retrospect, it was a simple mistake. The cooling water inlet, outlet, and drain valve were left in the closed position. The heat energy developed by the operating compressor... 

Block valve closed on cooling water inlet/outlets to exchanger". 

Cooling channels should be in parallel to the waterline and never in series. Each cooling outlet should be equipped with a valve to regulate the rate of flow independently. Plant cooling water is generally sufficient to keep the mold at about 15°-21 C (60 -70 F) but a cooler with a closed loop recirculation system can be used. 

Which type of valve one chooses is a safety issue, if upon a major failure the valve should go to the open position (for example cooling water) or closed position (for example reactants) should be judged by the engineer. If, for example, the valve is used at the outlet of a tank, we may want to close the valve to prevent all the liquid in the tank from being drained. 

The IC relies on the difference of densities between the IC hot leg and cold leg fluid to initiate and maintain a gravity-driven circulalion. Under station blackout conditions the reactor can be depressurized and cooled by first closing the main steam and feed-water isolation valves, followed by opening the IC coimection valve. The liquid column normally trapped by the coimection valve is allowed to flow into the reactor inlet. As fliis drains into the reactor, the IC heat exchanger tubing will be exposed to steam from the reactor outlet, allowing heat transfer to the reserve water pool. Further steam produced by the reactor due to the decay heat will sustain the circulation. 

The nitration of naphthalene to nitronaphthalene, according to Pascal [20a], is effected in a nitrator of the type shown in Fig. 108. The nitrator (1.16 m in diameter, 1.0 m high) is made of cast iron. The lower, conical part is provided with an outlet 5 cm in diameter, closed by a valve. The sheet iron jacket on the cylindrical part of the nitrator may serve a double purpose cooling the nitrator contents by water or heating by steam. 

With suitable safety precautions, a 12-oz. (see Note a) beverage bottle (internal capacity approximately 375 ml) is fitted with a rubber stopper equipped with both a gas inlet tube that can be closed off with a suitable valve and an exhaust tube that leads to a drying tube. The gas inlet tube should extend approximately half-way into the bottle. This equipment is tared. The stopper and its tubes are removed, and 170 gm of doubly deionized and deaerated water is placed in the bottle followed by 0.2 gm of the suspending agent [vinyl acetate-maleic anhydride copolymer or poly(vinyl alcohol) such as Elvanol 50-42] and 0.2 gm of the initiator (lauroyl peroxide, benzoyl peroxide, or AIBN). The rubber stopper with its inlet and outlet tubes is attached to the bottle, the valve is closed, and the assembly is again tared. Then it is thoroughly cooled in a Dry Ice-acetone bath. While the bottle is in this bath, the gas inlet tube is attached to a cylinder of uninhibited vinyl chloride, and the valve on the gas inlet tube is opened. Then the cylinder valve is opened slowly, and vinyl chloride is passed into the bottle. 

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