A comprehensive multi-criteria decision-making system using analytical hierarchy process and decision tree tools to choose the best alternative for a refinery master plan

Selecting the best alternative for billions of dollars of investment requires a comprehensive decision-making system. In a complex decision-making problem, the best alternative should be selected from a list of candidate ones considering multiple evaluation criteria with different weights. This paper proposes a comprehensive decision-making system including a multi-criteria decision-making (MCDM) method to assist selecting objectively the best alternative (scheme) for a refinery master plan megaproject. Different schemes and evaluation criteria are identified according to the reports of an engineering consultant on various available technologies and interviews with experts. Each scheme includes using a unique refining technology and revamping existing units. Eight evaluation criteria are considered including one qualitative and one probabilistic to assess and rank various schemes. All the alternatives and the quantitative, qualitative, and probabilistic evaluation criteria are considered in a MCDM method called analytical hierarchy process (AHP). The qualitative criterion is converted to a quantitative one using a Likert scale and expert's opinions. In addition, the probabilistic criterion is rationally changed to deterministic using decision tree tool. Finally, the schemes are ranked objectively comparing the AHPs output figures for each of them. The top ranked scheme is best aligned with organisational goals.