Dynamical Life Cycle Assessment: Implications to Design and Operation of Industrial Processes(3/3)
Date Issued
2003-08-26
Date
2003-08-26
Author(s)
余政靖
DOI
912214E002038
Abstract
The life cycle assessment (LCA) offers a systematic
approach in identifying the potential in reducing
environmental burden throughout the product life
cycle. In this work, the dynamic aspect of the LCA is
studied. First, the well-known block diagram
analysis is incorporated in the LCA and the
implications of recycling to process dynamics are explored. The result indicates that, as the result of
the positive feedback from material recycling, the
overall production dynamics becomes much slower.
This implies a lack of flexibility as more and more
recycled materials are utilized in product
manufacturing and it cannot be foreseen without
incorporating dynamics in the LCA. In order to meet
the market demand, increased inventories for the raw
and recycled materials are needed to compensate the
slow recycle dynamic and a larger turn down ratio is necessary for the raw material processing plants. The
missing inventory, due to slow dynamics, can be
expressed analytically in terms of the recycle ratio and
the recycle time constant. It can be used for
legislating new recycle policies which can alleviate the
increased inventory and large turndown ratio problems
for the future processing plants. The results indicate
that the dynamical LCA provides a better assessment
of product life cycle and, moreover, only the recycle
ratio and recycle time constant are needed to complete
the analysis.
approach in identifying the potential in reducing
environmental burden throughout the product life
cycle. In this work, the dynamic aspect of the LCA is
studied. First, the well-known block diagram
analysis is incorporated in the LCA and the
implications of recycling to process dynamics are explored. The result indicates that, as the result of
the positive feedback from material recycling, the
overall production dynamics becomes much slower.
This implies a lack of flexibility as more and more
recycled materials are utilized in product
manufacturing and it cannot be foreseen without
incorporating dynamics in the LCA. In order to meet
the market demand, increased inventories for the raw
and recycled materials are needed to compensate the
slow recycle dynamic and a larger turn down ratio is necessary for the raw material processing plants. The
missing inventory, due to slow dynamics, can be
expressed analytically in terms of the recycle ratio and
the recycle time constant. It can be used for
legislating new recycle policies which can alleviate the
increased inventory and large turndown ratio problems
for the future processing plants. The results indicate
that the dynamical LCA provides a better assessment
of product life cycle and, moreover, only the recycle
ratio and recycle time constant are needed to complete
the analysis.
Publisher
臺北市:國立臺灣大學化學工程學系暨研究所
Type
report
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