Blowdown experiments

Figure 9. Change in the pressure drop across different core segments and cumulative oil production with time during the blowdown experiment with the Lloydminster system.

During the quasi-steady phase (about 100 ms) the base and exit pressures are nearly constant (Fig. 3). Indeed, the pressure in these experiments is much more constant than in many so-called blowdown experiments, in which nucleation and bubble growth typically occur in the bulk of the liquid (see, e,g.. Winters and Merte [8]). The difference between p ase PexU is the wave amplitude , in this case 0.53 bar. In the steady state the upstream pressure is approximately maintained by the thrust of rapid vaporization. The fact that the exit pressure is greater than the reservoir pressure (namely, 0) indicates that the flow is choked. The instantaneous pressure fluctuates with frequency components between 0 and about 2 kHz the strongest peaks are below 250 Hz. The rms pressure fluctuations are approximately 3% of the mean pressure for both and... 

Blowdown experiments from supercritical stagnation conditions... 

The steam flash drum is a device for steam recovery. Flash steam occurs at the drum where steam condensate or boiler blowdown experiences a drop in pressure causing some of the condensate or boiler blowdown to evaporate forming steam and thus produces steam at the lower pressure (Figure 15.11). For low-pressure condensate, flash steam is negligible and thus it is not worth to recover. However, for medium-and high-pressure condensate, it is important to recover flash steam. 

Gallagher, E. V., 1970, Water Decompression Experiments and Analysis for Blowdown of Nuclear Reactors, ITTRI-578-P-21-39,1.T.T. Res. Inst., Chicago, IL. (3)... 

These cost estimates are preliminary approximations for work within the DOE environment and are based on experience gained during the DUS demonstration at the LLNL gasoline spill site. Costs not specified in these estimates include disposal costs for boiler blowdown and equipment costs for off-gas treatment (D114523, pp. 10-12). 

The Lyondell plant (ARCO Chemical Company) operates one of the first industrial scale chromate recovery systems in the U.S. The chromate recovery system is located in the ethylene plant of the Channelview, Texas, chemical complex. It was designed to treat a 1100 GPM cooling tower blowdown stream containing a 20-25 ppm chromate (CrO, ). A strongbase anion resin is used to selectively remove the chromate. This unit was placed in service in June, 1976. Information presented in this paper is based upon operating experiences. Economic considerations are also included. 

For each test parameter, usually a graph is created so that one can identify set pressure point and blowdown. Note, however, that not all in situ tests available on the market are fully computer-controlled and some are also based on the operator s experience and ability to know exactly when the upwards auxiliary force is equal to the spring force. 

This study is on the development of high-purity isobutane production from isobutane-enriched stream by gaseous adsorption technology. Isobutane purification from Ci mixture, in which not only isobutane, but also n-butane and several kinds of Ct olefins in small or in trace are involved, is very difficult by a traditional distillation method because of their close relative volatilities between constituting components. The continuous layered 3-bed process in which was comprised of six steps as follows pressurization-1 by the cocurrent effluent gas from the other bed, pressurization-2 by isobutane (noduct, adsorption, cocurrent depressurization, countercurrent blowdown, and low pressure purge by isobutane product, was applied. From the experiment, isobutane product with over 99.9% purity and with the trace levels of olefin components could be obtained at ambient temperature. Silver impregnated cliq prefers to CMS for the removal of Ci olefins... 

Experiments have indicated that the desulfurization slag can be used for treatment of the blast furnace blowdown wastewater for removal of residual suspended solids and all objectionable soluble components except ammonia. The removal of soluble heavy metals from industrial effluents by application of tliis slag may be performed at a broader pH range than required for hydroxide or sulfide precipitation alone. 

The performed experiments indicated that the desulfurization slag was effective in treatment of a simulated wastewater containing 50 mg/L of zinc, over a broad pH range, and in the treatment of the blast furnace blowdown wastewater. In the latter case the treatment was effective in removal of all objectionable soluble components of the wastewater except ammonia. 

Recycle is necessary to achieve the flowrate to suspend the bed and to allow solute concentrations to build to a steady state. A blowdown of solutes is provided via sample collection. Back reactions should be prevented and experiments are designed to be far from equilibrium . Chou and Wollast (1985) found that dissolved aluminum inhibited further dissolution rates of albite even at concentrations below the solubility limit for gibbsite. With the fluidized-bed apparatus (Fig. 6), they could control the aluminum concentrations to a low level at steady state by withdrawing sample at a high-rate. 

The SFE conditions are shown in Table 2. In Table 2 note that the temperature of the solid trap is changed between the extraction and reconstitution steps. During the optimisation of the SFE method, it was observed that a higher temperature in the trap during reconstitution greatly improved the efficiency of that step and the overall sample preparation process - i.e., the solubility of the fat in the solvent was increased so that less reconstitution solvent was necessary, resulting in smaller fraction output volumes (one vial) and less time spent in reconstitution and subsequent blowdown for the gravimetric measurement. The final method incorporated all of the conditions of Table 2 and experiment Set 4 from Table 1. The combined pre-SFE sample manipulation process then yielded a 99 % recovery of a... 

This phase is to establish and measure steady state operating conditions prior to initiating the transient or blowdown phase of the experiment. 

In this study we present theoretical considerations for Laval nozzle flows of a large-heat-capacity fluid at pressures and temperatures including the critical region. The corresponding experiments show phase changes close to the critical point during blowdown from supercritical stagnation conditions. 

The recoveries improve markedly with the experience of the analyst. Nitrogen blowdown with column is significantly improved using dichloromethane as the solvent. 

Blowdown recovery At the end of high pressure laboratory experiments, additional oil is recovered when the pressure is lowered, and a similar effect should be noted toward the end of a field displacement, but this production will, of course, only be realized in the final stages of the process. 

According to experiments performed under appropriate conditions, about 1% of the fission product iodine present in the flashed primary coolant volume is transported with the steam phase, about half of it in form of aerosols (Aim and Dreyer, 1980). This figure agrees well with that reported by Morell et al. (1985) and Hellmann et al. (1991), obtained in flashing experiments from small-diameter pipes (see Section 6.2.2.). In the experiments of Aim and Dreyer (1980), which were carried out in an uncoated steel vessel, only particulate iodide and elemental h were detected in the atmosphere of the vessel. The rate of plate-out of iodine from the atmosphere was found to depend on the specific geometric conditions of the experimental setup. In a comparatively small vessel, deposition halftimes of 8.5 hours for h and of 0.9 hours for aerosol iodide were measured within the first two hours after blowdown these values increased to 9.9 and 5.7 hours, respectively, during the following 22 hours. From other experiments markedly different values have been reported (e. g. CSE tests, see Section 7.3.S.3.8.). The reasons for these differences are not only due to the dimensions and true surface areas present in the respective experimental facility, but also to various other parameters, such as initial concentrations, turbulences in the atmosphere, rate of water droplet plate-out and of steam condensation. 

One of the most important integral experiments including severe core damage was the Loft FP-2 test, conducted in 1985 in the US Loss of Fluid Test Facility (which was shortly described in Section 6.2.1.3. and schematically shown in Fig. 6.4.). In this experiment, the performance and the results of which were summarized by Carboneau (1990), a pipe break in the low-pressure injection system was simulated, representing an accident initiated by a small break event. The cold-leg line of the intact loop served as the primary blowdown pathway prior to fission product release. During the period of fission product release, only the broken line of the low-pressure injection system was open consequently, fission products... 

For this experiment, the reactor core had been equipped with a central fuel module containing 100 pre-pressurized fuel rods, the UO2 fuel of which had been enriched to 9.7% and which had been pre-irradiated to a bumup of about 450 MWd/t U. The transient phase started with the reactor scram and was terminated about 30 minutes later when the external temperatiure on the surface of the shroud of the central fuel module reached 1517 K at this time, the highest measured cladding temperature reached 2100 K. When reflooding of the reactor core with emergency coolant was started, a rapid temperature excursion occurred within the central fuel module which was caused by the enhanced metal—water reaction. The transient was followed by a post-transient period of 44 days during which the reactor core was cooled by recirculating coolant and the concentrations of fission products deposited in the primary coolant system as well as their behavior in the blowdown suppression tank were measured. 

The data obtained in the measurements showed that about 1% of the iodine inventory of the central fuel module reached the blowdown suppression tank, while only 0.23% of the cesium inventory appeared there. These data and those taken from the simulated broken line indicated that cesium deposited in this line more readily than iodine the reverse situation occurred in the upper plenum of the reactor pressure vessel. Here, almost no cesium was detected on the deposition coupons while iodine was present in amounts similar to those in the line of the low-pressure injection system. Besides iodine, silver was found on the upper plenum coupons in equivalent amoimts in addition, the iodine deposited on these coupons could not be leached by water, indicating that it was present there as an insoluble compound. From these data it was concluded that fission product iodine was transported out of the reactor core as Agl, rather than as Csl. Formation of Agl as the main iodine compound deposited in the upper plenum of the reactor pressure vessel is a behavior markedly different from that observed in other in-pile experiments and in the TMI-2 post-accident investigations. The reason for this behavior was assumed to be the low concentrations of both cesium and iodine present in the low-bumup fuel, which resulted in a very high stoichiometric excess... 

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