Investigation of the Effect of the Efficiency of Catalysts on Early Destruction of Direct Reduction Reformer Tubes

The catalysts of the direct reduction unit play a significant role in producing reducing gases and the lifetime of the reformer tubes. In this paper, reducing the efficiency of catalysts on the early destruction of direct reduction reformer tubes will be investigated. Cold compressive strength test, XRF, and BET analysis were performed on intact and used catalysts. Also, the microstructure of the destroyed tube was examined by a scanning electron microscope, and the sulfur amount was measured. The results show that in used catalysts compared to intact catalysts, the specific surface area is reduced, and the access amount to areas containing nickel is reduced. Access to nickel-rich areas will be drastically decreased, and reforming reactions will not be performed well. This lessens the efficiency of the catalysts and breaks them down; hence several reformer tubes are exposed to higher temperatures, and their service life will be considerably reduced. Due to precipitations, the sulfur amount available in the destructed tube is equal to 0.1%, ten times the allowable sulfur content in the reformer tube alloy.