List of top Plant Design and Economics Questions asked in GATE CH

For purchasing a batch reactor, three alternatives \( P \), \( Q \), and \( R \) have emerged, as summarized in the table below. For a compound interest rate of \( 10\% \) per annum, choose the correct option that arranges the alternatives, in order, from the least expensive to the most expensive. \begin{table}[h!] \centering \begin{tabular}{|c|c|c|c|} \hline & P & Q & R
\hline Installed Cost (lakh rupees) & 15 & 25 & 35
\hline Equipment Life (years) & 3 & 5 & 7
\hline Maintenance Cost (lakh rupees per year) & 4 & 3 & 2
\hline \end{tabular} \end{table}

Consider the process in the figure for manufacturing \( B \). The feed to the process is 90 mol% \( A \) and a close-boiling inert component \( I \). At a particular steady-state:
- \( B \) product rate is 100 kmol \(h^{-1}\)
- Single-pass conversion of \( A \) in the reactor is 50%
- Recycle-to-purge stream flow ratio is 10
The flow rate of \( A \) in the purge stream in kmol h^-1, rounded off to 1 decimal place, is ___________ 

The capital cost of a distillation column is Rs. 90 lakhs. The cost is to be fully depreciated (salvage value is zero) using the double-declining balance method over 10 years. At the end of two years of continuous operation, the book-value of the column, in lakhs of rupees, rounded off to 1 decimal place, is___