BEST
Biochemical Engineering Simulation Technology
Abstract
The idea of developing a process simulator that can describe biochemical engineering (a
relatively new technology area) was formulated at the National Renewable Energy Laboratory
(NREL) during the late 1980s. The initial plan was to build a consortium of industrial and U.S.
Department of Energy (DOE) partners to enhance a commercial simulator with biochemical unit
operations. DOE supported this effort; however, before the consortium was established, the
process simulator industry changed considerably.
Work on the first phase of implementing various fermentation reactors into the chemical process
simulator, ASPEN/SP-BEST, is complete. This report will focus on those developments.
Simulation Sciences, Inc. (SimSci) no longer supports ASPEN/SP, and Aspen Technology, Inc.
(AspenTech) has developed an add-on to its ASPEN PLUS (also called BioProcess Simulator
[BPS]). This report will also explain the similarities and differences between BEST and BPS.
ASPEN, developed by the Massachusetts Institute of Technology for DOE in the late 1970s, is
still the state-of-the-art chemical process simulator. It was selected as the only simulator with the
potential to be easily expanded into the biochemical area. ASPEN/SP, commercially sold by
SimSci, was selected for the BEST work. SimSci completed work on batch, fed-batch, and
continuous fermentation reactors in 1993, just as it announced it would no longer commercially
support the complete ASPEN/SP product. BEST was left without a basic support program.
Luckily, during this same time frame, AspenTech was developing a biochemical simulator with
its version of ASPEN (ASPEN PLUS), which incorporates most BEST concepts.
The future of BEST will involve developing physical property data and models appropriate to
biochemical systems that are necessary for good biochemical process design.

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