Design and stabilization of direct autothermal methane steam reformation reactor for producing hydrogen via optimizing oxygen distributed feeding.

Direct autothermal methane reforming is an energy-efficient way of hydrogen production. However, significant hot spot is always encountered near the reactor inlet, causing catalyst sinter and even reactor damage. Hence, bed temperature regulation by oxygen distributed feeding was numerically investigated using a one-dimensional heterogeneous model. Simulation results show oxygen feeding along full length of reactor leads to low methane and oxygen conversion despite avoiding hot spot. Elevating feeding temperature solves this problem, but requires extra heat. Shortening feeding length to 1/10 of reactor reduces maximum bed temperature by 100 K; Half oxygen fed into reactor inlet and the other along the length further reduces maximum bed temperature and avoids the transient runaway. Optimization results show that oxygen parabolically and totally fed along the front part of the reactor length shows better performance than that feeding half along reactor length and the other into reactor inlet. • Various O 2 feeding for autothermal methane steam reforming was studied in detail. • Maximal reactor temperature reduced avoiding runaway as 1/2 O 2 fed along 1/10 length. • O 2 parabolically fed along the front part of the reactor is the best to suppress hotspot. [ABSTRACT FROM AUTHOR]