A particulate-accommodating fluid flow directing apparatus comprises a failure detection housing containing a flow directing insert, the housing serving as a pressure boundary; failure at any location along the insert being detectable by means associated with the housing. The insert can be manufactured of erosion resistant materials, including non-ductile materials such as ceramics. The insert is sealed to the housing at an inlet and a discharge forming a pressure chamber between the insert and housing. The pressure chamber can be maintained at a pad pressure complementary to the process pressure, the pad pressure being maintained and monitored for indication of insert failure.

Some embodiments of the present invention provide components for a serpentine fluid reactor which is optimized for one or more objective functions of interest such as pressure drop, erosion rate, fouling, coke deposition and operating costs. The components are designed by computer modeling the components individually and collectively in which the cross section of flow path is substantially circular under industrial conditions to validate the model design and its operation. Then iteratively the component designs are deformed and the operation of the deformed part(s) is modeled and compared to values obtained with other deformed models until the value of the objective function is optimized (e.g. at an extreme) or the change in the objective function is approaching zero.