(219i) Sustainable and Intensified Design of a Biodiesel Production Process

Sustainable
and intensified design of a biodiesel production process

Seyed S. Mansouri¹,
Muhammad I. Ismail¹, Deenesh K. Babi¹, Jakob K.Huusom¹,
Rafiqul Gani¹

seso@kt.dtu.dk, s101298@student.dtu.dk,
dkbabi@kt.dtu.dk, jkh@kt.dtu.dk, rag@kt.dtu.dk

¹CAPEC, Department of
Chemical and Biochemical Engineering, Technical University of Denmark, Building
229, Søltofts Plads, Kongens Lyngby, Denmark

Abstract

The growing concerns
about the global warming and greenhouse gas emissions (GHG) have led to an
increase in the interest to produce fuel from biomass and from the fact that
such fuels can relieve the reliance on imported oil and price. To this end,
numerous production facilities are being set up, at different scales and using
different methods of manufacture based on different raw materials and component
properties [1]. It is therefore timely to study the sustainability and
feasibility of these various manufacturing routes. Therefore, finding the best
alternative and design with minimum environmental impact and maximum
profitability is needed.

In this work a
computer-aided framework for process synthesis and process intensification is
applied for sustainable production of biodiesel from pure/waste palm oil as the
feedstock. This approach examines several
biodiesel processing routes that were collected through available data
and current technologies reported in the
literature. Using this information, a generic superstructure of processing
routes was created that described a network of configurations representing
multiple designs for the production of biodiesel. Therefore, based on the currently
known technologies, this superstructure includes
all possible alternatives. The next step was to analyze the superstructure
in  terms of economic and sustainability metrics. This was  done by first
performing simulation to obtain the steady state mass and energy balance data for
the entire superstructure. These data were then used for a sustainability analysis
[2] where a set of calculated closed- and open-path indicators were employed  to
identify the structural bottlenecks within the superstructure. Based on this
analysis the number of process alternatives within the superstructure was reduced
and a set of feasible flowsheet alternatives were identified. These were
further reduced through  economic and lifecycle assessment analysis (LCA) to
determine the alternative that best matched a specified set of performance
criteria (or design targets). A rigorous simulation was performed on this flowsheet,
which at this stage was considered as the base case design for the next step of
the framework.

To further improve the base
case design, process intensification was considered [3] with the targets set by
LCA, economic and sustainability analyses in the previous step. Out of the
three available levels for achieving PI, the phenomena-level, which is the
lowest level of aggregation, was considered so that potentially new and
improved alternatives to the base case design could be obtained. The objective
(or target) for the intensified process design was to overcome the bottlenecks
of the base case design. The optimization problem was further refined in terms
of logical, operational, structural constraints, using a PI knowledge base
tool. The next step was to identify the phenomena representing the tasks
performed within the base case design and the operating window of each phenomenon,
by applying thermodynamic insights [4] and the PI knowledge base.  Next, the
phenomena needed to overcome all identified process bottlenecks were identified,
sorted in terms of operation (task) types and the phenomena present in them, and,
screened using structural, operational and thermodynamic information. Note that
different combinations of phenomena can perform the same specified task. The
phenomena were then combined according to a set of rules to form unit
operations, which in turn were combined to form new and innovative process
alternatives. Finally, from the remaining set of feasible intensified process
alternatives, the best in terms of economic and environmental sustainability
was identified. For the case of biodiesel production, the intensified process
alternative turned out to be the most economical and more sustainable than
other alternatives.

The
computer-aided methods and tools used in this work are: SustainPro
(method and tool for process sustainability analysis), ECON (method and
tool for process economic analysis), LCSoft (method and tool for process
lifecycle assessment analysis) and process simulation software (e.g. PRO/II,
ASPEN Plus, ICAS). They are all used in an integrated framework for process
synthesis.

References:

[1]
L. Simasatitkul, A. Arpornwichanop, R. Gani, ?Design methodology for bio-based
processing: Biodiesel and fatty alcohol production,? Computers and Chemical
Engineering, 2013. DOI: 10.1016/j.compchemeng.2013.01.018

[2]
A. Carvalho, H.A. Matos, R. Gani, ?SustainPro-A tool for systematic process
analysis, generation and evaluation of sustainable design alternatives? Computers
and Chemical Engineering, 50, 8-27, 2013.

[3]
P. Lutze, D.K. Babi, J. Woodley, R. Gani, ?A phenomena based Methodology for
Process Synthesis incorporating Process Intensification,? Industrial and
Engineering Chemistry Research, 2013. DOI: 10.1021/ie302513y

[4]
C. Jaksland, R. Gani and K. Lien, "Separation process design and synthesis
based on thermodynamic insights," Chemical Engineering Science, 50,
511-530, 1995.