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Want to know Approach to Equilibrium calculation for the naphtha steam reformer of refinery having reformer exit design methane slip of 2.85 mol% dry basis. I have information on calculation of approach to Equilibrium (ATE) if wet base composition at reformer and shift converter is available. In this case steam/gas ratio can be calculated directly based on moles of H2O available. Normally this is not available from lab. They are giving dry analysis at reformer and shift converter outlet. Based on reformer inlet feed flow, steam flow, C/H of feed, recycle gas ratio, inlet pressure, PDI accross reformer and dry composition at exit of reformer and shift converter; is it possible to calculate ATE. If anyone have develop such formula/corelations please share with me so that I can know the catalyst activity and present ATE of reformer and HT shift converter.
 
Answers
08/08/2012 A: Gene Yeh, Saudi Aramco, gene.yeh@aramco.com
If you know your feed composition and flow rate, steam flow, dry gas composition and P(out) and T(out) at the reformer outlet, you can calculate dry gas flow rate at the reformer outlet by doing carbon balance. Once you know dry gas flow rate at the reformer outlet you can calculate steam flow at the reformer outlet by doing oxygen balance. Then you can calculate equilibrium constant for the actual steam reformaing reaction, and find T(eq). ATE for steam reforming reaction is equal to T(out)-T(eq).
You can apply the same method, basically, to calculate ATE for the high temperature shift reaction. ATE for shift reaction equals to T(eq)- T(out).