Emergency shut-down

The startup of the production unit was exciting. The extended surface cooler on the discharge end was installed and about half of the design pressure was used to avoid ignition. In spite of this, on the first day an ignition was observed and emergency shut down was activated. Removing the bottom closure it became evident that the square form of the cooler... 

Heat exchanger-like, multi-tube reactors are used for both exothermic and endothermic reactions. Some have as much as 10,000 tubes in a shell installed between tube sheets on both ends. The tubes are filled with catalyst. The larger reactors are sensitive to transient thermal stresses that can develop during startup, thermal runaways and emergency shut downs. 

In the range below 1 10 mbar the relationship between the ion flow and partial pressure is strictly linear. Between 1 10 mbar and 1 10" mbar there are minor deviations from linear characteristics. Above 1 10 mbar these deviations grow until, ultimately, in a range above 10 mbar the ions for the dense gas atmosphere will no longer be able to reach the ion trap. The emergency shut-down for the cathode (at excessive pressure) is almost always set for 5 10 mbar. Depending on the information required, there will be differing upper limits for use. 

PILOT VALVE 25 fl EMERGENCY SHUT DOWN SYSTEM... 

Propane refueling systems do not need elaborate control systems. The dispenser controls operation of the transfer pump, and emergency shut-down switches should be mounted near the dispenser and at some location between 6.1 m (20 ft) and 30.5 m (100 ft) from the dispenser. 

No control system beyond a start-stop switch on the dispenser for the transfer pump is needed. An emergency shut-down switch should be installed at a location remote from the dispenser that will shut down all the electricity to the dispensing station. 

Hydrogen dispensers will likely make use of programmable logic controllers or PC-based control systems. Both liquid hydrogen and compressed hydrogen dispensers will need to be able to monitor pressures and temperatures, open and close valves, turn on pumps, and interface with fire and emergency shut-down systems. 

NFPA 57 recommends that LNG dispensers be protected from collisions with vehicles and that they incorporate an emergency shut-down system. The maximum delivery pressure of the dispenser shall not exceed the operating pressure of the LNG tanks on the vehicle being refueled, and the LNG delivery hoses must have a shut-off valve at the end and a breakaway valve in the event a vehicle drives off with the refueling hoses attached. Bleed and vent valve must be incorporated into the dispensing lines to allow them to be drained and depressurized prior to disconnection if necessary. 

An example of a fixed-volume leak is a ruptured pipeline. Once the pipeline breaks, it must be isolated using emergency shut down valves. Thus, only the volume contained in the pipeline will leak, perhaps slightly more until the emergency procedures are activated and completed. 

G EMERGENCY SHUT DOWN SYSTEM ESO OPERATION WHEN PILOT ... 

PILOT VALVE 25 emergency shut Down system... 

Conducting event driven actions such as adding antifoam upon the detection of excess foam or invoking an emergency shut down routine if an exothermic reaction goes beyond controllable limits. 

Larger plants are preferably equipped with two or more lines fed by one large compounding (batching or formulation) system. Otherwise the lines are kept separate to improve availability because only one line is down during maintenance and emergency shut-downs. 

The two first events are associated with the reactor start-up tests. However, the two last ones, although they initiated an emergency shut-down thank to the "fail-safe" design of the reactor protection system, present the problem of its reliability. 

Algorithm of the SG emergency shut-down includes the following procedures ... 

The danger of solvent being sucked back from the still into the boiler in the event of an emergency shut-down must be guarded against. Since many boilers have volatile amines and other chemical additives in them, it is important to ensure that these are not unacceptable in the solvent product. 

An incident that required building or job site evacuation An incident that required emergency shut down of operations An incident that could incite public interest... 

What are the effects of changes of state of the media in case of deviations from nominal operating conditions (e.g. state of aggregation, viscosity, interfacial tension) Are the plant and its parts designed properly as to process conditions, structural strength and materials for the cases normal operation, start-up, shut-down and emergency shut-down ... 

What are the temperature and composition of off-gases during start-up, normal operation, extreme operating conditions, shut-down, emergency shut-down or malfunctions Is the safe discharge and removal of pollutants from off-gases ensured Are off-gas stacks and flares etc. properly dimensioned ... 

Batch STR used for polymerization and, to a lesser extent, nitration, sulfonation, hydrolysis, neutralization and, to a much lesser extent, dehydrogenation, oxidation and esterification can pose potentially unsafe operation. Key indicators of such potential hazards include Sudden increase in pressure , Unexplained increase in temperature , Failure of the mixer , Power failure , and Loss of cooling water . For any of these conditions our first question should be emergency shut down Our knowledge of the MSDS information for the species and their interaction with each other and with the environment is critical. 

Table 4. HEPs for Action Field supervisor decides to press the emergency shut down button ...

The results from the apphcation of the FPE for the second human action namely Field supervisor decides to press the emergency shut down button are show in Table 4. The HEP estimated for the initial situation is 5 X 10 . In this case there is available space for improvements in CPCs quality (Procedures and Plans and Crew Collaboration are rated in the average level, while Number of Simultaneous Goals is High for the field supervisor) which may decrease the probability of the erroneous action. 

Computer emergency shut down logic that discriminates from a group of inputs the input that tripped first to cause a shutdown. It may also be called First-Up Alarm. First Responder... 

There is a diverse emergency shut down system which is initiated manually if it is not possible to insert the control rods. It allows for injection of boron into the reactor. Since inadvertent operation of this system must be completely prevented, it requires insertion of a spool piece to connect the boron tank to the reactor. The negative moderator temperature coefficient is sufficient to maintain the reactor in a hot shut down condition for several days until the spool piece can be inserted. 

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