Economic appraisement on replacement of catalyst

Wenshan Wang et al. had discussed catalyst replacement. ° Zuxi Yu et al. took a chilled converter with four beds used in some ammonia plants with capacity of l,000t d as an example, applied REACTOR program to calculate the effect of catalytic activity on productivity, forecast the time to replace the catalyst in normal condition of production as well as forecast the economic benefits of output increment probably obtained after the replacement. Someone brought forward that the influence of the service time of catalyst on the economic benefits of the plant is appraised by the efficiency of converter (a), and a is token as a judgment of catalyst replacement. The efficiency of converter a is defined as  

Synthesis efficiency of converter can truly reflect the situation of the activity of catalyst, and the comprehensive level of energy consumption of synthesis loop to a great degree. At the same time, the data can be an important criterion for the evaluation of the economic efficiency of enterprises. Synthesis efficiency is not only determined by the catalytic activity, but also influenced by loop pressure, temperature, ratio of H2 to N2, space velocity and other reaction conditions which are a comprehensive reflection of running situation of synthesis system. In the same 

Compressor Rotation speed/ (r- min ) Design power/kW Designed flow/ (kg-h-i) Outlet pressure/ MPa Added power when converter efficiency drops by 1%/kW 

On the contrary, it can be seen from Table 9.19 that the efficiency of converter can be improved by using high activity catalyst. For example, in both the situations with similar conditions and with the same ammonia output, the efficiency of converter of ZA-5 catalysts increases by 4.13% and 5.79% than AllO, respectively. According to the data of Table 9.26, the power of the three compressor units can decline by 1383-1938kW, and its energy-saving effect is very significant. 

As a result, the catal3dic activity influences significantly the efficiency of the catal3dic process. In the existing converters, the substitution of high activity catalyst to low activity catalyst can greatly increase the economy of production process. 

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