Carbon deposition in the catalytic partial oxidation of methane to synthesis gas

Abstract

Publisher Summary The process of catalytic partial oxidation (CPO) of natural gas to produce synthesis gas has the potential to replace conventional steam reforming, with a substantial reduction in plant size. The process has recently been demonstrated in a fixed bed monolithic reactor (Davy McKee/Engelhard), and in a fluidized bed reactor (Exxon Research & Engineering). Both versions use steam as well as oxygen (1.0 and 0.5 steam/methane respectively). The avoidance of carbon deposition is paramount to the fixed bed process. In achieving this, the use of steam has the penalty of leading to high CO 2 selectivity from the water gas shift reaction, correspondingly restricting the CO selectivity achievable. It has long been considered that partial oxidation catalysts based on nickel lead to carbon deposition, while catalysts based on rhodium have a unique ability to avoid it. More recently, the extent of carbon deposition over the highly active ruthenium pyrochlores developed by Oxford University has been questioned. This chapter reports the work done to assess the conditions under which carbon deposition can be minimized over CPO catalysts with steam-free CH 4 /O 2 feeds.