Dump line

Dump the reactor contents into a vessel which contains cold diluent. This option also requires particular care that the dumping line is not blocked or does not become blocked during the dumping procedure. 

In applying FMEA, a mechanical flow diagram must first be developed.. As an example, consider the check valve on a liquid dump line. It can fail... 

Practical considerations of unloading play a major role in batch-mass reactors. For "low conversion reactors, a suitably sized dump line must be chosen, based on acceptable N2 dump pressure in the reactor, or discharge pump capability, as well as consideration for limiting reaction in the line between batches. 

Each sump must have its own drainage facilities. This is best achieved by installing an external valved dump line at a low point to interconnect the liquid outlet lines from each siunp (see Fig. 15.4a). Alternatively, a number of holes can be drilled at the bottom of the baffle, but this gives slow drainage rates and susceptibility to plugging and is therefore not recommended. The author is familiar with cases when it took over a day to drain the reboiler sump via such holes. 

A dump line connecting the bottom of the column with the reboiler liquid inlet line should be provided (Fig. 4.7a to d). Without it, liquid will weep through the tray at startup (there is no vapor flow until the reboiler starts up), and no liquid will be available to commission the reboiler and initiate vapor generation. 

Liquid dump lines These can help speed up column draining. 

Rgura 15.4 Techniques for overcoming thermosiphon reboiler problems. (a) The dump line technique and the throttling valve technique (6) residue removal from reboiler base (c) water accumulation to solve a water-induced reboiler surging problem. 

Installing a valved dump line connecting the column bottom outlet line with the reboiler inlet line (Fig. 15.4a). This technique is only needed when the column reboiler sump is separated from the column bottom sump by a baffle or when the reboiler liquid comes from a trapout pan. The valve remains shut during normal operation, but is opened during startup to lower the level and inspire thermosiphon action during startup. One case where this technique was successfully used has been described (237) the author has had several similar experiences. 

A once-throu thermosiphon reboiler could not be started up because tray weeping at startup starved the reboiler of liquid. A valved dump line cotmect-ing rdxriler liquid and bottom sump was added and solved problem. 

FIGURE 2-9 Dump line speeds draining (courtesy Oil Gas Journal). 

While two crewmembers are raising the top head, the third rhember of the team should verify that water is draining freely from the coke drum. Sometimes, due to formation of hot coke or the late addition of steam to the bottom nozzle after the switch, the flow of water from the bottom nozzle is restricted. This problem can best be observed by using the "dump line" shown in Figure 2-9. 

These valves are prone to leaking through, which results in gas being lost. Such a leak is identified by comparing the scrubber temperature with the temperature of the scrubber-liquid dump line downstream of the level-control dump valve. Any noticeable temperature drop across this valve is indicative of a significant loss of gas. 

II - steam supply to reheater, 12 - sodium expansion tank, 13 - steam- sodium reaction products dump line. 

The turbine trip which automatically closes the turbine throttle, simultaneously opens a dump line to the condenser. System pressure is automatically maintained using an in-line control valve and the reactor is kept in operation. 

When a fault arises disconnecting the turbo-alternator from the grid, the turbine stop valve is closed rapidly and at the same time a valve opens the dump system, which by-passes the turbine, to the condenser. This dump line Includes a control valve similar to the turbine contrpl valve which can also be ganged electrically to the speeder gear or preset manually to any position, say 100 open. When the turbine stop valve shuts, the pressure error signal is switched to control the dump control valve so that excessive change In pressure is avoided and pressure control maintained. 

Fiebeger, W. SCHELLHORN, M. 1994. Industrial minerals in soil sealants and waste dump linings. Industrial Minerals, 317, 41, 43, 45-47. 

Vessel closure. The bolted head closure utilizes two Flexitallic gaskets (asbestos encased in stainless steel), having a low-pressure Icakoff between gaskets. The internal diameter of the closure is slightly greater than G ft, to allow for the core tank removal. Similar bolted joints are provided in the inlet and outlet piping connections to the core as well as in the core tank dump line. 

Two dump lines, each with a maintainable valve, connect each loop with the dump tanks. 

---