Agriculture Reference
In-Depth Information
critical insights into the crop growth properties, such as salinity, nutrient status,
stress levels, and yield. These insights can then be used to provide site-specifi c crop
management strategies such as fertilization, irrigation, and weeding.
• Harvesting: Harvesting converts an energy crop in the fi eld into feedstock mate-
rial. It is considered a vital operation during the production of biomass feedstock.
The effi ciency of the harvester in maximizing the biomass collection is very
important. A typical harvesting system can include functions such as cutting,
conditioning, chopping, baling, and wrapping. Different confi gurations, such as
self-propelled against pull type or one-pass against multiple-pass, can be used
depending on the type of feedstock and equipment performance.
• Transportation: This task includes the conveyance of the biomass feedstock
within the farm (short distance) as well as from farm to biorefi nery or a central
storage facility (long distance). Different modes of transportation include truck,
rail, pipeline, barge, or a combination of these. Transportation is an unavoidable
and essential task and has been identifi ed as the major cost contributor in the
overall system. The costs and energy consumption depend on crop type, bulk
density, particle size, densifi cation levels, transportation mode, and infrastruc-
ture availability. All of these must be studied to achieve maximum effi ciency.
• Storage: This task aims to preserve biomass using processes that minimize total
quantity and quality loss as well as biomass recalcitrance. Storage task includes
on-farm open or covered storage as well as ensilage and dedicated storage such
as a central/satellite storage facility that is typically covered and enclosed from
all sides. Storage is important because improper storage can result in total dry
matter loss, microbial deterioration, generation of chemicals inhibitory to con-
version, and even combustion of the biomass. The benefi ts of high production
yields and economical conversion to fuel will be nullifi ed if suitable storage pro-
cedures cannot be developed to interface between the two.
• Preprocessing: Apart from the four major tasks listed above, various processing
operations can be performed on the biomass as a part of these tasks. For example,
drying operation is often a subtask in biomass storage [
16
]. Also included in this
category are chemical treatments for long-term preservation of biomass or for
preliminary breakdown of cellular wall structures as a precursor to biorefi ning,
compacting or cutting of biomass for moisture removal, and biomass densifi ca-
tion to optimize materials handling and increase vehicle transport payloads [
17
].
Milling has also been proposed as a potential pretreatment option.
•
Biorefi nery: The biorefi nery utilizes the biomass feedstock made available by the
preceding tasks. The feedstock may be used to produce fuel, heat, power, and/or
value-added products. Each of these desired end products requires different process-
ing routes, which may govern the optimal scale of the biorefi nery. It may also impact
the quantity and quality constraints of biomass that is delivered to the biorefi nery.
These operations are impacted by knowledge and developments in crop sciences,
chemical and biochemical sciences, chemical engineering, economics, law, regula-
tion, policy, and sustainability. Figure
1.1
also shows these extraneous factors.
In the next section, we describe a typical BFPP system that may be implemented
based on the current knowledge and understanding. This description is based along
the lines of different tasks described above.
Search WWH ::
Custom Search