Super-high-pressure steam

Fig. 1. Typical heater configuration. BFW = boiler feed water SSH = super high pressure steam HP = high pressure and ID = induced draft..

Fig. 51eft. Schematic flow diagram of an ethylene plant using naphtha feedstock. CW = cooling water QW = quench water QO = quench oil LPS = low pressure steam MPS = medium pressure steam SPS = super high pressure steam C3R = propylene refrigerant and...

Two-circuit heat removal system with steam-water cycle of supercritical parameters is very difficult for realization, because super high pressure steam generator ( 250 atm) should be located inside the reactor vessel (BREST concept), and there is a real possibility of the core blockage by the products of water and heavy coolant interaction resulting in the core melt- down. Such incident took place in the propulsion reactor cooled by PbBi [7.11],... 

Evergreen Nylon Recycling LLC, a joint venture between Honeywell International and DSM Chemicals, was in operation from 1999 to 2001. It used a two-stage selective pyrolysis process. The ground nylon carpet, without separation, was dissolved with high-pressure steam and then continuously hydrolyzed with super-heated steam to form caprolactam. With a 100 thousand tons per year capacity, the program diverted over one hundred thousand tons of post-consumer carpet from the landfill to produced virgin-quality caprolactam. - ... 

As for the turbines, no steam-purifying equipment of the type used on drum boilers is feasible, so that the steam from super-critical boilers tends to be of inferior quality. Deposits have been reported of cuprous oxide on the extra high-pressure turbines and of cupric oxide on some high-pressure turbines of sub-critical plant. These deposits may lead to a loss of efficiency and to some risk of corrosion. At intervals, slugs of solute are carried over in the steam, which is therefore of fluctuating quality. This is countered by periodic water-washing of the boilers. 

In steam turbine power plants, steam pipes carry super heated vapor under high temperature (1050°F/565.5°C) and high pressure often at 3500 psiMPa or greater. In a jet engine temperatures may reach to 1000°C, which may initiate creep deformation in a weak zone. For these reasons, it is crucial for public and operational safety to understand creep deformation behavior of engineering materials. 

Commercial alkaline electrolysis occurs at temperatures up to 150 °C and pressures to 30 bar,96 and super critical electrolysis to 350 °C and 250 bar.102 Although less developed than their fuel cell counterparts which have 100 kW systems in operation and developed from the same oxides,103 zirconia and related solid oxide based electrolytes for high temperature steam electrolysis can operate efficiently at 1000 °C,104,105 and approach the operational parameters necessary for efficient solar... 

High-pressure cylinder 2 - Low-pressure cylinder 3 - Generator 4 - Steam super-heater 5 - Separator 6 - Turbine condenser ... 

Reviews of high temperature water and steam cooled fast reactor concepts from the 1950s to the mid 1990s are described in Appendix B grouped as supercritical pressure water cooled reactors nuclear super heaters and steam cooled fast reactors. 

A layout for the Super LWR NPP is drawn in Fig. 3.2 [2]. It is a two-loop system. The supercritical steam flows into the turbine system through the outlet nozzles of the RPV and the main steam lines. The water is pumped out of the condenser by a series of pumps and back to the reactor through the inlet nozzles. A series of low pressure and high pressure feedwater heaters are placed upstream and downstream from the main feedwater pumps, respectively, to preheat the cold water before it flows into the reactor. The safety system design and characteristics are discussed in Chap. 6 in detail. 

A dry type containment like that of PWRs is also considered for the Super LWR as illustrated in Fig. 3.3b. As the Super LWR has no steam generator, a high pressure and intermediate pressure combined turbine and a startup system (see Sect. 5.7) are installed inside the containment in this example to effectively utilize the space in the containment and therefore make the turbine building more compact. 

The pressure suppression type containment like that of BWRs is a candidate for the containment of the Super LWR and Super FR. The steam temperature and pressure discharged into the suppression pool through the vent pipes or safety relief valve (SRV) pipes will be higher than those in BWRs. Especially from the SRV pipes, superheated steam or supercritical steam may be discharged. The characteristics of its condensation in the subcooled water at low pressure (containment pressure) need to be well understood. Kyushu University researchers carried out a unique experiment to observe condensation behavior with a high speed camera and to measure pressure oscillation of vapor discharge into a subcooled liquid pool [38]. HCFC123 was used in this experiment and the experimental apparatus is shown in Fig. 8.7 [38]. 

Since the Super LWR plant system does not have a superheater, the main steam conditions need to be adjusted during startup and low power operations. The enthalpy of the core outlet coolant must be high enough to provide the required turbine inlet steam enthalpy. At subcritical pressure operation in the sliding pressure startup scheme, boiling and dry out in the descending moderator water rods are undesirable and should be prevented because they affect the inlet subcooling. 

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