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EST Plant (Eni Slurry Technology) consists of about 300 pressure vessels in the following principal units and section: * EST unit (unit 90); * Hydrogen production plant (Unit 95); * SWS sulphur recovery and tail gas treatment (Unit 92 and 94). More than 100 "critical" equipments exist in the EST complex, divided in units and sections on the basis of their type of service. In detail, the considered critical items include: carbon steel and low alloy steels heavy wall pressure vessels for high temperature, high-pressure hydrogen service; carbon steel pressure vessels in sour (wet H^S service) and amine service. For fabrication of such "critical" items special base materials and filler metals were adopted according to specific material requirement, special welding processes and fabrication sequences (including advanced automatic systems for non destrucutive testing) were used. This paper shows an overview on some critical aspects and experience of fabrication of main "critical" equipments of EST Plant. [ABSTRACT FROM AUTHOR]

This paper has the target to summarize which are the fillers to be used in the pressure vessels cladding processes. We evaluate the most common requests in the customer's specifications and how to meet them while checking the results during construction. We gave great emphasis to the applications with austenitic stainless steels (series 300), without neglecting other applications such as Ni-based alloys. We evaluated the different processes to be used and the role of "b ferrite" which, besides being often a specific requirement of the customer, is also the key factor to control the cladding during the construction. We examined the various processes used in terms of thickness and dilution. The dilution is a key output, which depends on the process used and the parameters reported in the WPS. The accurate assessment of the dilution allows to choose the most suitable filler material and to avoid problems. The power source must be reliable and allow the repeatability of the process, as well as having a "duty cycle" adapted to production demands. It is important to underline that often being the surface to be plated several hundred square meters, the correct selection of the power sources reduce the cycle times and the delivery times. In fact, very often the cladding is on the production critical path. We presented some real cases, demonstrating how it is possible to meet the specification requirements with a careful analysis of a few experimental data. We dedicated a chapter to cladding repair defects subject. Cladding repairing defects need to be evaluated on a case by case basis, but in this presentation we propose some key guidelines that can be used to develop the repair specifications avoiding common problems. [ABSTRACT FROM AUTHOR]