## 3 Case Study of Boiler System Used in Textile Process Industries
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multirow{2}{*}{**Failure Mode**} & \multirow{2}{*}{**Failure Cause**} & \multirow{2}{*}{**Failure Effect**} & \multirow{2}{*}{**Failure Effect**} & \multirow{2}{*}{**Proficiency in the Field**} & \multirow{2}{*}{**Scale**} \\  & & & & & & & & & \\ \cline{4-9}  & Short term overheating & & Starvation of steam or water flow & Axial fish-mouth rupture & 4.25 & 3.22 & 2.63 & 3.29 & 2.56 & 3.07 \\ \cline{2-9}  & & Blockages from debris & Axial fish-mouth rupture & 4.48 & 3.99 & 2.67 & 3.39 & 2.37 & 3.24 \\ \cline{2-9}  & Thin lip failure of the tube & Due to rapid heating & Rupture & 4.47 & 3.67 & 2.86 & 2.80 & 2.02 & 3.34 \\ \cline{2-9}  & Tube joints failure & Dissimilar metal welds & System failure & 4.78 & 3.38 & 2.63 & 3.29 & 2.16 & 3.20 \\ \cline{2-9}  & Crack and holes & Calcium and magnesium layer increases & The boiler should be closed & 5.03 & 3.45 & 2.38 & 3.15 & 1.93 & 3.45 \\ \cline{2-9}  & Tube surface corrosion & Due to the presence of moisture content & Tube failure & 3.81 & 2.60 & 2.51 & 2.60 & 1.61 & 2.65 \\ \hline Deposits formed in the top of the drum & due to refractory brick deterioration & partially blocking the blowdown channel ports & 4.29 & 3.09 & 2.30 & 2.99 & 2.09 & 2.78 \\ \hline Boiler tube blisters/bulges & Due to presence of internal scale & Tube failure & 4.94 & 2.95 & 2.92 & 2.66 & 1.97 & 3.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Decision matrix A for PSI. The value of the attribute must be dimensionless in multi-attribute decision-making methods. For this reason, the attribute value is converted between 0 and 1, which is known as normalization. All six parameters of this analysis are minimization criteria, i.e., lower attribute values are preferred. The normalization of the decision matrix-A is performed by using Equation (2) and the results are shown in Table 10.  
\(\bullet\) **Step 6:** Compute the mean value of the normalized data. \begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline
**Component** & **Failure Mode** & **Failure Cause** & **Failure Effect** & **SV** & **O** & **D** & **M** & **S** & **L** \\ \hline \multirow{6}{*}{Water Tubes} & Short term overheating & \begin{tabular}{l} Starvation of steam or \\ water flow \\ \end{tabular} & Axial fish-mouth rupture & 0.5294 & 0.8079 & 0.7238 & 0.7245 & 0.4534 & 0.6446 \\ \cline{2-10}  & Blockages from debris & Axial fish-mouth rupture & 0.5026 & 0.6511 & 0.7107 & 0.7028 & 0.4898 & 0.6111 \\ \cline{2-10}  & Thin lip failure of the tube & Due to rapid heating & Rupture & 0.5034 & 0.7091 & 0.6636 & 0.8500 & 0.5743 & 0.5937 \\ \cline{2-10}  & Tube joints failure & Dissimilar metal welds & System failure & 0.4709 & 0.7696 & 0.7220 & 0.7238 & 0.5375 & 0.6188 \\ \cline{2-10}  & Crack and holes & \begin{tabular}{l} Calcium and magnesium \\ layer increases \\ \end{tabular} & \begin{tabular}{l} The boiler should be \\ closed \\ \end{tabular} & 0.4472 & 0.7533 & 0.7994 & 0.7548 & 0.6005 & 0.5742 \\ \cline{2-10}  & Tube surface corrosion & \begin{tabular}{l} Due to the presence of \\ moisture content \\ \end{tabular} & Tube failure & 0.5900 & 1.0000 & 0.7560 & 0.9148 & 0.7198 & 0.7462 \\ \cline{2-10}  & Deposits formed at the top & \
\begin{tabular}{l} Due to refractory brick \\ deterioration \\ \end{tabular} & Partially blocking the & 0.5249 & 0.8423 & 0.8279 & 0.7969 & 0.5546 & 0.7127 \\ \cline{2-10}  & Boiler tube blisters/bulges &
\begin{tabular}{l} Due to the presence of an \\ internal scale \\ \end{tabular} & Tube failure & 0.4552 & 0.8829 & 0.6499 & 0.8942 & 0.5883 & 0.6502 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Normalized decision matrix for PSI.