Conduit system for conveying fluids is described. The conduit system comprises a conduit, a tubular, and a sealing component. The tubular is positioned radially interior of an inner surface of the conduit along a length. The tubular comprises a polymeric material. The sealing component is positioned proximate the distal end of the tubular in an annulus formed between an outer surface of the tubular and the inner surface of the conduit, the sealing component constructed and arranged to seal the annulus. Methods for reducing corrosion of or providing pressure integrity to a conduit are also described.