چكيده به لاتين
Iron oxide-based catalysts are one of the most widely used ammonia synthesis catalysts in the petrochemical industry. Promoters such as SiO2, Al2O3, MgO, CaO and K2O are used in the production of ammonia synthesis catalyst. In this research, the effect of lanthanum and cobalt improvers on KM1 commercial catalyst was investigated. Catalysts were synthesized by melting and casting method. XRD, TPR, SEM, XPS, XRF, BET and catalytic activity tests were used to investigate the effect of promoters. The results showed that lanthanum did not change the reduction speed compared to the KM1 and increased the reduction temperature from 939 to 1000 ˚C. In the presence of lanthanu, BET increases from 11.97 m2.g-1 to 12.95 m2.g-1 and the catalytic activity decreases from 4.25 to 92.3 % mole of NH3. Cobalt increases the rate of reduction by 0.04 mmol/g.min, which is equivalent to reducing the reduction time in proportion to the initial time of 0.8. From an industrial point of view, a 24-minute reduction in reduction process in an industrial unit under high pressure and temperature is significant. In the presence of cobalt promoter, BET increases to 12.12 m2.g-1 and the catalytic activity decreases to 11.4 % mole of NH3. From all the results, it can be claimed that lanthanum is in the category of structural improvers for magnetite-based catalysts, and the addition of cobalt does not have a significant effect on the catalytic activity, and on the contrary, it increases the kinetics of the reduction reaction. The simultaneous addition of cobalt and lanthanum to the catalyst, reduces the reduction temperature of the M-K catalyst to 20 ˚C. This achievement is a significant number in ammonia production industry. Because it significantly reduces energy consumption and costs. In addition, the effect of improvers was studied on the most widely used catalyst in the petrochemical industry, therefore, the results of this research can be directly used in catalyst production industry.
