# Risk Identification of FPSO Oil and Gas Processing System Based on an Improved FMEA Approach
## 5 Discussion
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{6}{c}{**Improved Fuzzy TOPSIS**} \\ \hline \multicolumn{2}{c}{**Subjective-Variable Integrated Weight**} & \multicolumn{2}{c}{**Subjective-Entropy Integrated Weight**} & \multicolumn{2}{c}{**Fuzzy TOPSIS**} \\ \multicolumn{2}{c}{**Method**} & \multicolumn{2}{c}{**Method**} & \\ \hline
**Failure Modes** & \(C_{n}\) & **Ranking** & \(C_{n}\) & **Ranking** & \(C_{n}\) & **Ranking** \\ \hline FM\({}_{1}\) & 0.043 & 2 & 0.156 & 3 & 0.163 & 3 \\ FM\({}_{2}\) & 0.033 & 9 & 0.130 & 8 & 0.134 & 8 \\ FM\({}_{3}\) & 0.036 & 6 & 0.138 & 5 & 0.145 & 6 \\ FM\({}_{4}\) & 0.035 & 7 & 0.131 & 7 & 0.135 & 7 \\ FM\({}_{5}\) & 0.034 & 8 & 0.126 & 9 & 0.131 & 9 \\ FM\({}_{6}\) & 0.037 & 5 & 0.137 & 6 & 0.146 & 5 \\ FM\({}_{7}\) & 0.026 & 12 & 0.106 & 12 & 0.110 & 12 \\ FM\({}_{8}\) & 0.029 & 11 & 0.119 & 10 & 0.123 & 10 \\ FM\({}_{9}\) & 0.051 & 1 & 0.191 & 1 & 0.199 & 1 \\ FM\({}_{10}\) & 0.040 & 4 & 0.151 & 4 & 0.155 & 4 \\ FM\({}_{11}\) & 0.041 & 3 & 0.159 & 2 & 0.163 & 2 \\ FM\({}_{12}\) & 0.031 & 10 & 0.116 & 11 & 0.112 & 11 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Ranking Comparison. necessary to attract the attention of decision-makers. According to the calculated results, the primary separator and fuel gas scrubber have the highest risk of gas leakage, while crude oil separator has the highest risk of oil leakage. In summary, by comparing the calculated results of improved fuzzy TOPSIS and fuzzy TOPSIS, it is verified that the former is reasonable and effective in introducing fuzzy evidence reasoning and the comprehensive weighting method, and solves the problems caused by the uncertainty, diversity, and subjective weight of O, S, and D ratings. Therefore, the proposed approach can reduce the risk priority ranking error of failure mode and provide a more scientific basis for risk decision-making. The risk identification approach based on a fuzzy TOPSIS integrated fuzzy evidential reasoning approach is proposed in this paper. In specific applications, the implementation process of the method will be limited due to the limitation of the number of experts, but in \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{\(\alpha\) = 0} & \multicolumn{2}{c}{\(\alpha\) = 1} & \multicolumn{2}{c}{\(\alpha\) = 2} & \multicolumn{2}{c}{\(\alpha\) = 3} & \multicolumn{2}{c}{\(\alpha\) = 4} \\ \hline
**Failure Modes** & \(\mathbf{C_{n}}\) & **Ranking** & \(\mathbf{C_{n}}\) & **Ranking** & \(\mathbf{C_{n}}\) & **Ranking** & \(\mathbf{C_{n}}\) & **Ranking** & \(\mathbf{C_{n}}\) & **Ranking** \\ \hline FM\({}_{1}\) & 0.037 & 4 & 0.043 & 2 & 0.052 & 2 & 0.063 & 1 & 0.076 & 1 \\ FM\({}_{2}\) & 0.034 & 8 & 0.033 & 9 & 0.033 & 9 & 0.032 & 9 & 0.032 & 10 \\ FM\({}_{3}\) & 0.034 & 7 & 0.036 & 6 & 0.036 & 7 & 0.036 & 7 & 0.037 & 7 \\ FM\({}_{4}\) & 0.034 & 6 & 0.035 & 7 & 0.036 & 6 & 0.037 & 6 & 0.037 & 6 \\ FM\({}_{5}\) & 0.033 & 9 & 0.034 & 8 & 0.035 & 8 & 0.036 & 8 & 0.037 & 8 \\ FM\({}_{6}\) & 0.035 & 5 & 0.037 & 5 & 0.040 & 5 & 0.042 & 4 & 0.045 & 3 \\ FM\({}_{7}\) & 0.027 & 12 & 0.026 & 12 & 0.024 & 12 & 0.023 & 12 & 0.022 & 12 \\ FM\({}_{8}\) & 0.030 & 11 & 0.029 & 11 & 0.028 & 11 & 0.027 & 11 & 0.026 & 11 \\ FM\({}_{9}\) & 0.047 & 1 & 0.051 & 1 & 0.056 & 1 & 0.060 & 2 & 0.065 & 2 \\ FM\({}_{10}\) & 0.039 & 3 & 0.040 & 4 & 0.041 & 4 & 0.042 & 3 & 0.044 & 4 \\ FM\({}_{11}\) & 0.040 & 2 & 0.041 & 3 & 0.042 & 3 & 0.042 & 5 & 0.042 & 5 \\ FM\({}_{12}\) & 0.031 & 10 & 0.031 & 10 & 0.031 & 10 & 0.032 & 10 & 0.033 & 9 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Ranking comparison of taking different \(\alpha\) value (Improved fuzzy TOPSIS using the subjective-variable integrated weight method). Figure 6: Ranking comparison of taking different \(\alpha\) value (improved fuzzy TOPSIS using subjective-variable integrated weight method). specific embodiments, the implementations will be constantly updated with the increase in the number of experts and the wider adoption of opinions in the later stage, so as to get more convincing results.