Existence and localization of positive solutions for a nonlocal BVP arising in chemical reactor theory

•We improve the range of parameters that can be considered in the model.•The nonlocal BCs can be interpreted as feedback controllers for a chemical reactor.•We provide the existence and localization of multiple positive solutions.•The approach relies on classical fixed point index.

We discuss the existence of positive solutions of a nonlocal boundary value problem that models a chemical tubular reactor. Our approach allows us to deal with a wide range of parameters, nonlocal conditions and to provide upper and lower bounds for the solutions. We make use of the theory of fixed point index for compact maps. Some examples are presented to illustrate the theory.