The Use and Storage of Methyl Isocyanate (MIC) at Bayer CropScience (2012) / Chapter Skim
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6 A Framework for Decision Making
6 A Framework for Decision Making
Pages 113-130
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From page 113... ...
adopting an alternative chemical process not involving MIC, (3) using an alternative process for MIC production that would consume MIC immediately and thus not require storage, and (4)
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From page 114... ...
Liability for worker injury due to MIC exposure X ? Liability for worker injury due to dust exposure X Wastewater disposal requirements X X Length of time for regulatory approval X Internal/Cost Pressures Product purity X X Cost and availability of chemical feedstocks X X Capital costs X Equipment O&M costs X Costs of safety equipment ?
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From page 115... ...
The CCPS's observation from its 1995 book remains true today: "Decision aids have been applied only to a very limited extent in risk decision problems in [the chemical process] industry." The CCPS indicates key obstacles to adopting these tools include lack of familiarity with the tools among chemical process industry decision makers and fear that the methods are either too simple or too costly.
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From page 116... ...
However, as noted previously, MAU theory is not the sole method of approaching these difficult questions, although it is hoped that the discussion here will demonstrate the potential utility of these types of decision aids. Decision Sciences and MAU Models: Background The field of decision sciences emerged from the axioms of rational choice first posed by mathematician John von Neumann and economist Oskar Morgenstern in 1947.
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From page 117... ...
represents individual utility functions for each of the decision maker's n objectives, and the ki represents weights assigned to the different objectives. These weights reflect the value to the decision maker of an option that offers the best possible outcome along objective i, while setting all other objectives at their worst possible values.
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From page 118... ...
However, groups with disparate values may have differing utility functions that may lead to differences in the preferred manufacturing process. Although multiple MAU models may be needed to reflect different groups' values, these models can be extremely useful in guiding negotiations among groups in conflict (Raiffa et al., 2002)
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From page 119... ...
Keeney and McDaniels constructed a MAU model that BC Hydro then used to support decisions related to capital equipment upgrades, supply planning, and other corporate strategic issues. Keeney and McDaniels (1992)
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From page 120... ...
To small customers 511. Minimize outages (expected number of annual outages to a small customer annually)
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From page 121... ...
The best choice is not always clear." In this case, the automotive company, with support from decision analysts, used a MAU model to help decide which of the three vehicle frameandskin systems maximized the utility to the company, given the need to tradeoff cost and performance attributes. Thurston interviewed the decision makers at the company (in this case, engineering materials design managers focused on longterm fleet planning)
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From page 122... ...
for each of the five attributes, again through surveys of the decision makers, and the scaling constants ki for each utility function, as well as the overall scaling constant K As an example, Figure 6.1 shows singleattribute utility functions for operating cost and flexibility in number of body types possible per platform.
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From page 123... ...
123 A FRAMEWORK FOR DECISION MAKING FIGURE 6.1 Single-attribute utility functions for cost and flexibility for the auto industry case study described in Box 6.2. Note that the dots represent points on the utility function assessed through structured interviews with the company's decision makers.
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Limitations of Existing Inherent Safety Indexes Chemical engineers in the field of ISP design have conceived a number of summary indexes intended to capture the trade-offs in objectives embodied by
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From page 125... ...
The main theoreti cal weakness is that the indexes were not designed to follow the von NeumannMorgenstern model of rational choice, so there is no guarantee that the index value for a given manufacturing process will be able to reflect a given decision maker's actual preferences and attitudes toward risk. Perhaps more importantly, these indexes -- in contrast to a MAU approach -- do not allow for the possibility of multiple decision makers with different preferences.
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From page 126... ...
Extent to which process limits potential negative consequences of out-of- ISI5 = ISIl normal operations (e.g., by unit segregation) Attribute Category : Need for add-on processes to control hazards Representation in Attribute Description I2SI Equations Pressure control required PHCI1 = PHCIp Temperature control required PHCI2 = PHCIt Flow control required PHCI3 = PHCIf Level control required PHCI4 = PHCIl Concentration control necessary PHCI5 = PHCIc Inert venting necessary PHCI6 = PHCIiv Blast wall needed PHCI7 = PHCIbw Fire resistance wall needed PHCI8 = PHCIfr Sprinkler system necessary PHCI9 = PHCIs Forced dilution needed PHCI10 = PHCId on different attributes, a MAU model can reflect differences in risk tolerances in the form of the utility function: linear functions represent risk neutrality; concave functions represent a preference for gambling on high risks that have potentially high payoffs; and convex functions represent risk aversion (for details, see Cle men and Reilly, 2001)
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From page 127... ...
EMPLOYING MAU MODELS AT BAYER CROPSCIENCE MAU and ISP decision-making tools could have been used to inform manufacturing process design choices at numerous points in the history of the Institute pesticide plant, starting with the introduction of MIC to the site in 1978. As noted in Chapter 5, changes to the production process made at the Institute facility were generally considered in response to business conditions or external pressures, without explicit consideration of ISP principles.
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From page 128... ...
Implementing a structured, multi-attribute decision process such as MAU analysis may be easier when designing a new production process or an entirely new facility. In such cases, no incumbent process has an advantage in terms of capital costs or production uncertainties, since all the alternative processes are new and hence hypothetical.
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From page 129... ...
A new decisionmaking framework, incorporating some of the work done to develop existing ISP indexes but also allowing explicit consideration of differences in decision makers' preferences across multiple attributes, could assist in the incorporation of ISP considerations into decision making in the chemical manufacturing industry and communication of those considerations to a concerned public. Design decisions cannot be strictly objective with regards to ISP as these choices will always require trade-offs among attributes and varying levels of risk; different individuals or constituencies may have different value systems and thus make different trade-offs.
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From page 130... ...
2004. Integrated Inherent Safety Index (I2SI)
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