(380e) Distributed Small Scale Marine Biorefineries: Scale Analyses and Design for Developing Countries

Abstract

Distributed Small Scale
Marine Biorefineries: scale analyses and design for developing countries.

Alexander Golberg¹,
Gregory Linshiz², Nathan J. Hillson², J. D. Keasling, M. Koudritsky

Alexander Chemodanov³.

¹  Department of Mechanical
Engineering, Etcheverry
Hall, 6124, University of California  

at Berkeley, Berkeley, CA 94720
USA. and Center for Engineering in
Medicine and Department of Surgery, Massachusetts General Hospital, Harvard
Medical School, Boston, MA, USA

Email:
agolberg@gmail.com.

²  Joint
BioEnergy Institute ,Lawrence Berkeley National Labs, 1 Cyclotron Road,
Berkeley, CA 94720.

³  Independent researcher, 2-236
Duke st. W. Kitchener ON, Canada. 

⁴  Independent researcher, Milner 16b
Hadera P.B.20995, Israel. 

The major growth in liquid fuel demand over
the next 20 years will be predominantly due to developing countries. While
Gross Domestic Product (GDP) and primary energy production in Organization for
Economic Co-operation and Development (OECD) countries is not linearly
correlated, GDP growth in developing countries requires increases in primary
energy production. The World Energy Council predicts that India and
China will overtake developed countries in transportation fuel consumption by
2025. Due to climatic, economic, and fossil fuel resource constraints, there is
an urgent need for the sustainable, cost-effective production of carbon-neutral
transportation fuels.

Biofuels present
an alternative to fossil fuels. First generation biofuel technologies utilize
established processes and currently produce biofuels on a commercial scale.
First generation feedstocks include sugar beet, starch-bearing grains, and
conventional vegetable oil crops, and first generation fuel products include
ethanol and biodiesel. Second and third generation biofuel technologies,
currently in research and development, utilize animal fat, lignocellulosic
biomass, and algae feedstocks, and produce hydrotreated vegetable oil,
cellulosic-ethanol, biomass-to-liquids (BtL)-diesel, bio-butanol, and advanced
drop-in replacement fuels such as fatty-acid ethyl esters, bisabolene, pinene,
n-alkanes, n-alkenes, and methyl ketones.

Although
biofuels may collectively supply a portion of future transportation fuel
demand, competition between ?energy crops? and ?food crops? for land and water
resources is a growing concern. Furthermore, the extents to which land erosion,
potable water consumption, fertilizers, pesticides, and climate change impact
biofuel sustainability have yet to be evaluated .

While
significant efforts are being directed towards developing feedstocks and
conversion technologies, biorefinery design remains in its infancy. The
optimization of biorefinery size, feedstock, technology, and serviced area will
be required to reduce the costs of the resulting biofuel products.

Recent research
in constructal design shows that the optimal distribution of flows of products
and services across a populated area depends on a balance between the size of
the production centers with sizes of distribution networks that connect these
centers to end users. Although larger systems are thermodynamically more
efficient in production, they serve larger areas; thus, the collection and
distribution logistical costs also increase with size. Therefore, a balance
exists between efficiencies of scale, and system distribution losses. This
balance has been investigated both for thermodynamics of energy sources and
economics of agricultural/biofuel systems. Applications of the balance
principle have been demonstrated for the thermodynamical optimization of hot water
flow and heating, refrigeration, combined solar power and desalination, and
agricultural product processing economics. The balance principle has also lead
to proposals for ?distributed energy systems? to optimize energy production
size and service area.

The goal of this work is to show that the balance between
thermodynamic efficiency of system size, collection and distribution is valid
for biorefineries. This work also aims to demonstrate that population
characteristics, such as density and per capita liquid fuel consumption, play a
critical role in the design of biorefinery size, technology choice and serviced
area.

 We report a
model macro algae biorefinery design for midsize towns in low to medium income
countries with low liquid fuel consumption per capita. We targeted these
populations since the majority of new fuel systems built in future years will
serve their growing demands. We focus our model on macro algae, a promising
biofuel crop feedstock that does not compete with food crops for arable land or
potable water. Furthermore, macro algae, which do not contain lignin, are
convenient candidates for cost effective processing with current technology. We
analyze biorefinery production of a transportation biofuel from the green macro
algae Ulva sp, and demonstrate the integration of this model biorefinery
into the distributed energy systems. For example, we analyze a system that would
supply all the liquid fuel needs of a 20,000 person coastal town in a middle
income country, where the annual per capita demand is 26 gallons of liquid fuel
per year. The designed system consists of an open controllable photobioreactor
and a consolidated bioprocessing unit, which yields renewable liquid fuel. We
propose to use a green seaweed Ulva as a biomass source. The analyses of
prior studies shows that Ulva yields of 15-22 kg dry weight∙ m^-2
∙year ^-1, with a heating value of about 19 MJ∙kg^-1,
can be achieved with 200 W∙m^-2 solar radiation with a zero
pesticide footprint. With current ethanol/seaweed conversion rates, a 30 ha
cultivation farm, along with 8 ha of a photo-voltaic (PV)
facility to provide operational energy, is required to satisfy the liquid fuel
demands of a middle income town in a developing country. The system is easy to
operate and maintain, and can be manufactured and installed in multiple
locations. Finally, in the context of a single biorefinery,
we compare macro algae with corn grain and cassava feedstocks.