کاربرد روش دلفی فازی و AHP فازی در انتخاب فن آوری احیای لوبریکانت

Due to the funding scale and complexity of lubricant regenerative technology, the selection of recycling technology and policy for waste lubricant oil can be viewed as a multiple-attribute decision process that is normally made by a review committee with experts from academia, industry, and the government. This study aims to provide a systematic approach towards the technology selection, in which two phase procedures are proposed. The first stage utilizes Fuzzy Delphi Method to obtain the critical factors of the regenerative technologies by interviewing the foregoing experts. In the second stage, Fuzzy Analytic Hierarchy Process is applied to find the importance degree of each criterion as the measurable indices of the regenerative technologies. This study considers eight kinds of regenerative technologies which have already been widely used, and establishes a ranking model that provides decision makers to assessing the prior order of regenerative technologies. The empirical study indicates that the “Proper scale” is the most important evaluation criterion considered in overall experts. The demonstration of how the prior order of regenerative technologies changes under various domains of experts is addressed as well.

The efficient recycling of waste lubricant could help reduce both the environmental pollution and gas emission from greenhouses, thus, creating a huge efficiency either from environmentally-friendly or economic levels. Waste lubricant recycling and regeneration not only save the cost of lubricant, but also contribute to environmental protection. The proper management of dispose and recycling of the waste oil becomes critical to the management of environment (Cheng, Lin, Chang, & Huang, 2006/1). Regenerating waste oil into chemical feedstock or fuel oil is one of the preferred recycle methods. At present, there are eight kinds of common lubricant recycling technologies as follows: (1) acid/clay process; (2) distillation process; (3) solvent de-asphalting process; (4) TFE + hydro-finishing; (5) TFE + clay finishing; (6) TFE + solvent finishing; (7) solvent extraction hydro-finishing and (8) TDA + clay finishing and TDA + hydro-finishing. These technologies are different in economic benefit, technology maturity and environmental impact, and new technologies have been developed and applied continuously. The government shall be responsible for technology assessment, and combine the views of academia, industrial circles and government sectors to set up a measuring index for selection of lubricant recycling technology. The traditional Delphi Method, developed by Dalkey and Helmer (1963), has been widely used to obtain a consistent flow of answers through the results of questionnaires (Hwang & Lin, 1987; Reza & Vassilis, 1988). Delphi is an expert opinion survey method with three features: anonymous response, iteration and controlled feedback and finally statistical group response. However, some weaknesses have been exposed, it needs repetitive surveys to allow forecasting values to converge which requires much more time and cost (Hwang and Lin, 1987 and Ishikawa et al., 1993). Furthermore, in many real situations, experts’ judgments can not be properly reflected in quantitative terms. Some ambiguity will result due to the differences in the meanings and interpretations of the expert’s opinions. Since people use linguistic terms, such as ‘good’ or ‘very good’ to reflect their preferences, the concept of combining fuzzy set theory and Delphi was proposed by Murray, Pipino, and Gigch (1985), and named the Fuzzy Delphi Method (FDM). Lubricant regenerative technology selection is a multiple criteria decision-making problem. Among these, the Fuzzy Analytic Hierarchy Process (FAHP) is one of the most popular (Kahraman et al., 2004, Teng and Tzeng, 1996 and Zhau and Goving, 1991). People often use knowledge that is imprecise rather than precise. The fuzzy set theory approaches could resemble human reasoning in use of approximate information and uncertainty to generate decisions. It was specifically designed to mathematically represent uncertainty and vagueness and provide formalized tools for dealing with the imprecision intrinsic to many problems (Kahraman et al., 2004, Williams, 2003 and Zadeh, 1965). Consequently, to make this study more sensible and gain a more representative description of the decision-making process, this study would apply the FAHP to investigate which evaluation criterion is the most important in overall technical committees. This study contains two stages: the first stage is to establish the key factors for evaluation of the waste lubricant recycling technologies, and use FDM by consulting experts of academia, industries and government sectors to select a technological selection criterion, in order to find out the important factors to be considered while selecting a technology; the second stage is based on FAHP, and consults experts of various fields to find out the importance of various criteria, in order to obtain the measuring index for selecting lubricant recycling technology.

This study investigates the key factors in lubricant regenerative technology selection by combining FDM, SAM and FAHP, and establishes objective and standardized references. A total of 17 factors influencing lubricant regenerative technology selection are analyzed through FDM experts’ opinions investigation, Experts of academia, lubricant oil industry and government sectors were interviewed, and 12 evaluation criteria were obtained as the key factors by interviewed bank experts. SAM and FAHP were used to integrate experts’ opinions to obtain the significance evaluation of various evaluation criteria given by experts in group decision. The results from experts of different fields were compared and analyzed to show the similarities and differences of various experts in lubricant regenerative technology selection. Finally, the results of all experts were used as the evaluation index of lubricant regenerative technology selection. The following conclusions were reached by analyzing the evaluation criteria stressed by experts of various domains when evaluating the lubricant regenerative technology selection based on the demonstration of this study. 1. Experts of various domains lay different emphasis on three main aspects: The experts of academic community lay similar stress on three aspects; only the technology aspect has a slightly higher weight. This is probably because the experts of academic community include those of environmental industry, chemical industry, machinery, electric machinery and so on, therefore the three aspects have relatively mean score on weight; the industrial circles lay emphasis on the technology and economy aspects, the weight of environmental protection aspect is obviously low; the government sectors pay attention to the environmental protection aspect, since they care about whether lubricant regenerative technology will generate secondary pollution or not. Due to various domain experts give quite different weights to different aspects; it is necessary to collect all opinions of different domain experts in the course of lubricant regenerative technology selection, so as to make the evaluation more objective and feasible. 2. Experts of various fields pay quite different attention to evaluation criteria in environmental protection aspect: Although the environmental protection aspect has minimum weight, four evaluation criteria in it make experts from three domains have most difference in their opinions. Due to “PCB removal” and “hazardous chemical substances used”, these two evaluation criteria because more severe secondary pollution, they are stressed by experts of academic community and government sectors, but the industrial circles don’t. Therefore, the government legislates and sets a baffle plate for the evaluation criteria in environmental protection aspect, and eliminates heavy-pollution technical proposals in advance. 3.Technology aspect is mostly concerned: Due to many technical proposals are still in experimental development stage, or there are a few successful commercial operations, experts of various domains lay stress on the performance of technology aspect, among which, three evaluation criteria such as “development stage”, “recovery rate” and “product quality” rank the second to fourth place in the global priority sequence, its degree of importance is obvious. 4. Proper scale of technology is the most important evaluation criteria: There are quite much waste lubricant oil in Taiwan, however, too many demands of waste lubricant oil recovery processing cannot be satisfied yet, The waste lubricant oil recovery volume and the scale of potential competitors within the regional extent should be considered in the course of lubricant regenerative technology selection, therefore, it is very important to select “proper scale” technical proposal.