Startup schematic


The second step is to estimate the direci instaUation costs by summing all the cost factors involved in the direct installation costs, which include piping, insulation, foundation and supports, and so on. The sum of these factors is designated as the DCF (direct instaUation cost factor). The direct installation costs are then the product of the DCF and X. The third step consists of estimating the indirect instaUation costs that is, all the cost factors for the indirect instaUation costs (engineering and supervision, startup, construction fees, and so on) are added the sum is designated by ICF (indirect installation cost factor). The indirect installation costs are then the product of ICF and X. Once the direct and indirect installation costs have been calculated, the total capital cost (TCC) may be evaluated as follows  [c.2170]

On the second startup no ignition in the bottom occurred, but it was observed here also that a significant drop in oxygen concentration occurred between the reactor bottom and the heat exchanger, without loss of acrolein concentration. The homogeneous reaction also produced acrolein, just in much lower selectivity. Then, on the third day of  [c.131]

A TPG block diagram is shown in Figure 4-86. It is similar to the FCC diagram except a second inlet valve is added to assure trip action and a bypass valve is added to reduce overspeed and aid in startup. The only rotating elements are the expander and generator and, possibly, gear (Figure 4-87).  [c.193]

The startup speed and temperature acceleration curves as shown in Figure 19-2 are one such safety measure. If the temperature or speed are not reached in a certain time span from ignition, the turbine will be shutdown. In the early days when these acceleration and temperature curves were not used, the fuel, which was not ignited, was carried from the combustor and then deposited at the first or second turbine nozzle, where the fuel combusted which resulted in the burnout of the turbine nozzles. After an aborted start the turbine must be fully purged of any fuel before the next start is attempted. To achieve the purge of any fuel residual from the turbine, there must be about seven times the turbine volume of air that must be exhausted before combustion is once again attempted.  [c.636]

Accumulators can be used to help stabilize the lube system against pressure transients such as that from the turbine power operator during a large correction. For a sizing rule of thumb, the system pressure should not vary by more than 10%, while the turbine servo travels full stroke in a one second interval. The role of accumulators for pump switching was covered earlier in the section on Startup Control.  [c.317]

A chemical plant flare experienced a series of three consecutive deflagrations resulting in severe damage to the flare water seal flame arrester (Desai 1996). The deflagrations occurred during process startup after a complete unit shutdown. The first flashback from the flare is believed to have tilted the water seal internals such that it lost its effectiveness as a flame arrester. After operators reset both the natural gas and snuffing steam interlocks, the methane flow was reestablished to the flare, and steam flow was stopped. This resulted in a second flashback that was felt as a rumble by the operators. However, at this point, the water seal flame arrester was believed to be nonfunctional (as evidenced by recorded low pressure drop), allowing the flashback to travel into the knockout drum and cause an explosion. Production personnel once again reset the interlocks, and the same flashback scenario was repeated for a third time. This deflagration probably caused additional internal damage to the water seal. Overall damage was limited to the water seal only, and no one was injured.  [c.9]

The results in Table 8-3 show the three-column polishing of valine ester for the first cycle of use (start-up). Three columns are sufficient to polish the D-enantiomer to below detection levels. Hence, for actual operation two columns in series may well be sufficient. However, the data in Table 8-3 also show how the preferentially rejected L-enantiomer initially breaks through the three columns in series at fairly high enantiomeric purity (up to > 97 %) even out of just the first stage during startup or the first cycle. The data in Table 8-4 show the polishing results for two columns in series for the second cycle as the system begins to come to long-term equilibrium. Some D-enantiomer now begins to break-through the system. However, the ratio of L- to D-enantiomer breaking through the system of the total effluent volume is between 6 and 7. This is the equilibrium or a-based level due to the loading being 6 1 in favor of the D-enantiomer.  [c.213]

The second factor, speed transients, is a leading cause of gear-reliability problems. The momentary change in torsional load created by rapid changes in speed can have a dramatic, negative impact on gear sets. These transients often exceed the maximum horsepower rating of the gears and may result in failure. Operating procedures should ensure that torsional power requirements during startup, process-speed changes, and shutdown do not exceed the recommended horsepower rating of the gear set.  [c.580]

In the startup of a reactor, it is necessary to have a source of neutrons other than those from fission. Otherwise, it might be possible for the critical condition to be reached without any visual or audible signal. Two types of sources are used to supply neutrons. The first, appHcable when fuel is fresh, is califomium-252 [13981-174-Jwhich undergoes fission spontaneously, emitting on average three neutrons, and has a half-life of 2.6 yr. The second, which is effective during operation, is a capsule of antimony and beryUium. Antimony-123 [14119-16-5] is continually made radioactive by neutron  [c.217]


Turboexpanders and Process Applications (0) -- [ c.182 ]