Pressure vessel concept

A low-cost nickel-hydrogen system proposed by Eagle Picher is based on the multiple cell per single battery pressure vessel concept. Additional system cost reduction is proposed through use of standardized components, ease of manufacture and an inherent design versatility able to meet various voltage and capacity requirements with only minor modifications. 

Since its conception, the dynamic filter has been widely reported and further developed. Most European designs are comprised of a multistage disk arrangement (Fig. 28) with both the rotating and stationary elements covered with filter cloth, thus utilising the space inside the pressure vessel. Such filters have been found (29) to be from 5 to 25 times more productive in mass of dry cake per unit area and time than filter presses for the same moisture content of the final slurry. In some cases, the moisture content with the dynamic filter was actually lower than with a filter press. The maximum productivity was achieved with peripheral disk speeds from 2.8 to 4.5 m/s. 

This concept can be especially significant for a low-pressure vessel wl minimum wall thickness is desired. For example, assume the caiv .,.i i.ons for a 50-psig MAWP vessel indicate a wall thickness of 0.20 in., and it is decided to use K-in. plate. This same plate might be used if a MAWP of 83.3 psig were specified. Thus, by specifying the hi MAWP (83.3 psig), additional operating flexibility is available at e dally no increase in cost. Many operators specify the MAWP based on... 

TNT Equivalence. Explosion strength is often expressed as equivalent mass of TNT in order to permit estimates of possible explosion damage. For BLEVEs and pressure vessel bursts, using this equivalence is unnecessary because the methods mentioned above give explosion blast parameters which relate directly to the amount of possible damage potential. However, the concept of TNT equivalence is still useful because it appeals to those who seldom deal with blast parameters. For reasons explained in Section 4.3.1, BLEVEs or pressure vessel bursts catuiot readily be compared to explosions of TNT (or other high explosives). Only the main points are repeated here. 

Key features are the high reforming pressure (up to 41 bar) to save compression energy, use of Uhde s proprietary reformer design [1084] with rigid connection of the reformer tubes to the outlet header, also well proven in many installations for hydrogen and methanol service. Steam to carbon ratio is around 3 and methane slip from the secondary reformer is about 0.6 mol % (dry basis). The temperature of the mixed feed was raised to 580 °C and that of the process air to 600 °C. Shift conversion and methanation have a standard configuration, and for C02 removal BASF s aMDEA process is preferred, with the possibility of other process options, too. Synthesis is performed at about 180 bar in Uhde s proprietary converter concept with two catalyst beds in the first pressure vessel and the third catalyst bed in the second vessel. 

For testing, the Mod 2 burner is housed within a heavily walled pressure vessel which also serves as a plenum chamber for the preheated inlet air supply. See Ref. 16 for a description of the test facility. The burner assembly is shown schematically in Figure 2 and is designed to use 100% of the air flow in the combustion process. Thus, air film cooling and air dilution which are normally used in an engine combustor are omitted. In this way, combustion effects from air injection are avoided for the concept evaluation. The cylindrical combustion chamber is water cooled, as are the sonic exhaust nozzle and gas sample probe. 

The safe design of a pressure vessel takes into account the strength of the material and the stresses that are imposed on it by internal pressure and exterior forces. The approach to satisfactory design can be best understood with an appreciation of the equations of a thin-walled vessel. Expansion of these concepts to the implications of a thick-walled vessel will lead to the code rules written by the ASME. 

A module just described is a fixed module in which the membrane elements are stationary. A radical departure from the conventional mode of R.O. systems operations is the rotary system wherein externally wound membrane elements clustered around a central shaft are rotated in a stationary pressure vessel filled with pressurized feed stock. Here the separated permeate is replaced by an equivalent volume of fresh feed stock under a constant head. The basic rotary concept is depicted in Fig. 3. 

The FEE (analogue, e.g. pre-amplifiers etc.) reside in the base of the detector pressure vessel. FEE are devoted to the processing of signals generated by the absorption of X-Rays in the active volume of the MWPC. They comprise a fast spectroscopic amplifier connected in unison to anode wires, together with four cathode pre-amplifiers (Two for each cathode plane). The FEE extract the requisite positional, spectral and temporal information from the MWPC readout system. Moreover, implementation of the fast delay-line readout concept enables a nanosecond discrimination capability. 

New concepts based on passive safety presently under study are the Pebble Bed Modular Reactor (PBMR - gas cooled, high temperature, helium operated, direct cycle turbine generators) supported by an international group based in South Africa, the IRIS reactor (a PWR with steam generators integrated in the reactor pressure vessel) and the already mentioned APIOOO. Other concepts still under study but already proposed exist... 

The Karlsruhe Institute has installed another co-axial reactor concept mainly for corrosion studies (0.7 m of 12 mm id, 600°C, 50 MPa, 0.3 kg/h). The space between the two tubes, an outer pressure vessel and an inner tube made from ceramic material, is connected via a movable gasket to prevent pressure differences [26]. 

ETH Zurich developed the concept of a film-cooled coaxial hydrothermal reactor [36]. Two coaxial tubes form the reactor, waste water enters the central tube, and the oxidant enters the outer tube. The walls of the reactor are cooled by a water film of 80-250°C to retard precipitation of solids and corrosion of the pressure vessel. Hydrothermal flames, estimated at 1700-2200°C can be observed through windows. The plant was designed for 15 kg/h at 42 MPa and 600°C and was patented by Sulzer Chemtech AG 1995 in the USA [37]. 

The concept for multi-layer construction was first developed in Germany around 1890. However it was not until the 1930s that the concept became practical with the advent of electric arc welding. In the 1930s the A.O. Smith Corporation pioneered the concept of concentric wrapped thin layers and evenmally produced more than 10,000 multi-layered pressure vessels. The license was eventually sold to CB I who produced... 

In the ideal IPWR system, all the primary reactor cooling system components including the pumps (if required) and pressurizer are incorporated within the single primary reactor pressure vessel. A simplified drawing of a generic low-power IPWR concept that uses natural circulation without any primary pumps is shown in Figure 2. 

A brief tabulation (Table 1) identifies the key features of Advanced Reactor Concepts now being developed. The modular high temperature gas-cooled reactor (MHTGR) excels in most areas except capital cost the relatively high capital cost results from the low power density in the MHTGR pressure vessel (about 20% that of the AP600), and the cost of helium confinement systems. A second tabulation of the materials utilized for coolant, moderator and fuel in current or recent reactors was compiled (Table 2). Various combinations of coolant, moderator, and fuel were considered. 

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