Feasibility study of prestressed concrete pressure vessels for coal gasifiers

The use of prestressed concrete pressure vessels (PCPVs) for gasifiers in coal conversion systems has been examined by the Oak Ridge National Laboratory. Conceptual designs for commercial-sized vessels were developed based on an output of 2.64 x 108 MJ/day for the HYGAS process gasifier and 1.32 x 108 MJ/day for the Synthane process gasifier. Circular cylindrical configurations were employed for the single-cavity vessels. The geometry of the liners was essentially the same as proposed for the commercial steel vessel in both cases. The Synthane and HYGAS gasifiers both require numerous small penetrations. One large-diameter penetration is required in the top head. A removable multiplate steel structure serves as the closure for this large penetration. It is restrained by a series of short columns which provide for easy removal. Each vessel is posttensioned by circumferential strand windings which are confined and anchored in steel-lined precast concrete channels on the outside surface of the PCPV. Linear tendon clusters which are housed in steel ducts provide the axial prestressing. The results of these studies show that the use of prestressed concrete vessels in applications where large, heavy-walled, steel vessels are required is both technically and economically feasible. Further, the advantages of concrete over steel vessels for gasifiers are directly related to vessel size. (orig.)