Reduction and Analysis of Low Temperature Shift Heterogeneous Catalyst for Water Gas Reaction in Ammonia Production

摘要

In order to obtain additional quantities of hydrogen after the reforming reactions of natural gasand protect the ammonia synthesis catalyst, it is crucial to achieve and maintain maximum possibleactivity, selectivity and stability of the low temperature shift catalyst for conversion of watergas reaction during its lifetime. Whereas the heterogeneous catalyst comes in oxidized form, it isof the utmost importance to conduct the reduction procedure properly. The proper reductionprocedure and continuous analysis of its performance would ensure the required activity, selectivityand stability throughout the catalyst’s service time. For the proper reduction procedure ofthe low temperature shift catalyst, in addition to process equipment, also necessary is a reliableand realistic system for temperature measurements, which will be effective for monitoring theexothermal temperature curves through all catalyst bed layers. For efficiency evaluation of lowshift temperature catalyst reduction and its optimization, it is necessary to determine at regulartime intervals the temperature approach to equilibrium and temperature profiles of individuallayers by means of “S” and “die off” temperature exothermal curves. Based on the obtaineddata, the optimum inlet temperature could be determined, in order to maximally extend theservice life of the heterogeneous catalyst as much as possible, and achieve the optimum equilibriumfor conversion of the water gas. This paper presents the methodology for in situ reductionof the low temperature shift heterogeneous catalyst and the developed system for monitoring itsindividual layers to achieve the minimum possible content of carbon monoxide at the exit ofthe reactor. The developed system for temperature monitoring through heterogeneous catalystlayers provides the proper procedure for reduction and adjustment of optimum process workingconditions for the catalyst by the continuous increase of reactor inlet temperature. Theapplied system provides maximum catalytic activity, selectivity and stability, as well as enablesprediction of the catalyst's performance, which can be the basis for a proper decision on itstimely replacement, and significant reduction of production costs.