of sulfuric acid: in other words, two moles of
sodium hydroxide will be reacted with one
mole of sulfuric acid to be sodium sulfate as
solid. The filter (FILTER) is operated for the
separation of these solids. The distillation
columns (D2 and D3) are utilized to purify 107
kg/h of glycerol as USP grade (more than 93%
concentration).
3.2 Life cycle assessment
3.2.1 Result of inventory analysis
Inventory analysis involves data collection
and calculation procedures to quantify the
relevant inputs and outputs of a production
system. These inputs and outputs may include
the use of resources and releases to air, water,
and land associated with the system. Due to heat
used in this process coming from biomass,
pollutants releasing from biomass combustion
are mainly CH4 and N2O with 0.00003 kg/MJ
and 0.000004 kg/MJ, respectively [12]. Table 2
shows the overall inventory analysis of this
study obtained from the simulation.
3.2.2 Allocation method
The allocation of environmental impacts to
materials and products is a complex process.
The appropriate method also depends on the
perspective of the observer. Economic allocation
is one of common attribution allocation. Glycerol
and sodium sulfate (Na2SO4) are generated as
co-products during biodiesel production.
Quantity and price of co-product including
allocation factor from biodiesel production are
shown in Table 3.