Primary pressure

For the liquid-phase mass-transfer coefficient /cl, the effects of total system pressure can be ignored for all practical purposes. Thus, when using Kq and /cl for the design of gas absorbers or strippers, the primary pressure effects to consider will be those which affect the equilibrium curves and the values of m. If the pressure changes affect the hydrodynamics, then Icq, and a can all change significantly. 

Thus, when using kG,yand ki xfor the design of mass-transfer processes the primary pressure effects to consider will be those which affect the equilibrium curves and the values of... 

An inlet pressure about 10 times greater than the maximum pressure drop across the column was required. By going to inlet pressures of 100 atm, the flow should be controllable to 0.2%. The main problem with this technique is that if the column or any part of the system should plug, the pressure of the system prior to that point rises until it reaches the primary pressure. This can result in dangerously excessive pressures. 

Hydrotesting is required of primary pressure parts (usually nozzle, body and bonnet) at 1.5 times the design rating if the nozzle is larger than 25 mm or pressures from 20.7 barg and if it is cast or welded. 

Both full and semi-nozzles, bodies for seminozzle valves, bodies with integral nozzles, primary pressure-containing components of pilot-operated main valve... 

Primary pressure-containing parts of pilot valves (minimum main valve and cap)... 

Manometers consisting of liquid columns of, commonly, mercury or a fluid such as silicone oil, have been used extensively in the past to measure gas mixtures in, for example, experimental, static investigations of the overall kinetics of gas-phase reactions. They continue to be used in many applications, including the establishment of primary pressure standards in several countries. 

If a rupture disk is used as the primary pressure-relief device, then when it bursts the operators have no option but to shut down the plant so that the disk can be replaced before the vessel is repressured. Rupture disks are therefore most commonly used at the inlets of relief valves or as secondary relief devices. Rupture disks can be sized using equation 13.105 for compressible gases in sonic flow, with a value of Kd = 0.62. 

In the SUPRAYIELD process, the delayed decompression is a degenerated flash process slowed down to such an extent that the period of time for going from a high primary pressure to a lower secondary pressure corresponds to the reaction time needed for the desired conversion of pentosan to furfural. To make this a practical proposition, the primary temperature must be high, say 240 °C, and the secondary temperature should not be below 180 °C as in this range the reaction rate would be too slow. 

In the medium temperature reactors like SFR and SCWR, the pressure of chemical process can be different from the primary pressure. Usually, chemical equilibrium may be not favorable in medium temperature range for processing fossil fiiels, but such technology as the membrane separation could alleviate the disadvantage. 

The safety demonstration tests in the HTTR are conducted to demonstrate an inherent safety feature, that is an excellent feature in Shutdown of the HTGRs, as well as to obtain the core and plant transient data for validation of safety analsis codes and for establishment of safety design and evaluation technologies of the HTGRs. The safety demonstration tests consist of Reactivity insertion test - control rod withdrawal test and Coolant flow reduction test as shown in Figure 6. In the control rod withdrawal test, a central pair of control rods is withdrawn and a reactivity insertion event is simulated. In the gas-circulators trip test, primary coolant flow rate is reduced to 67% and 33% of rated flow rate by running down one and two out of three gas-circulators at the Primary Pressurized Water Cooler without a reactor scram, respectively. 

The reactor core and the steam generator are housed in two steel pressure vessels, which are connected by a connecting vessel. Inside the connecting vessel, the hot gas duct is mounted. All pressure-retaining components, which comprise the primary pressure boundary, are in touch with the cold helium of the reactor inlet temperature. 

IHX Intermediate heat exchanger PPWC Primary pressurized... 

Formation pressure data were obtained from repeat formation tester (RFT) or modular dynamic tester (MDT) measurements of numerous deep wells in the Central North Sea. These data were used as the primary pressure dataset as they are the most accurate pressure measurements possible down-hole. The MDT/RFT wireline tool takes a pressure reading within a permeable formation, by setting a seal at a precise depth determined by using an accompanying gamma ray tool for depth correlation. Drill stem test (DST), mudweight data and kick (influxes of pore fluids into the wellbore) information was also used where RFT or MDT data were not available or of very poor quality. A summary of the various approaches used to derive formation pressures is provided by Holm (1998). 

Ihe operating ejqjerience has shown that abnqit changes in a primary pressure can be the reason of damages in internal structures made as semi-closed plena which walls were not designed for the primary coolant pressure. That was the reason of feilure of a partition in the reactor coolant pump of icebreaker "Arctica". 

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