Environmental Engineering Reference
In-Depth Information
and is used for paper production; the lignin and hemicellulose parts, though,
dissolve and are further separated; the lignin is burned for steam production
and the hemicellulose is hydrolyzed to sugars with production of furanic
compounds for blending into transportation fuel. Which type of biorefinery
is this?
15.3
In the petrochemical industry, the production of olefins, in particular ethylene,
is important. This is the rawmaterial for polyethylene production. Now, based
on biomass, propose a thermochemical and a biochemical biorefinery concept
in which ethylene can be (co)produced. Can you say something about the
economics of these processes?
15.4
A consortium of parties decides to work out a biorefinery concept based on
rapeseed input only; it produces a biodiesel by transesterification with
methanol, crude glycerol stream, and a press cake that can be used as cattle
feed. The input is 675 t
d
−1
of rapeseed (consider it dry), and the press
d
−1
. Neglect catalyst input (KOH) needed. For
simplification, consider rapeseed oil as the triglyceride ester of oleic acid
(formula: CH
3
(CH
2
)
7
CH=CH(CH
2
)
7
COOH), which is the most important
oil constituent, and glycerol.
cake production is 375 t
a. How much methanol (t.d
−1
) would be needed at stoichiometric, complete
conversion? Can this be produced with minimal fossil footprint?
b. How much crude glycerol is produced?
c. Name some applications of glycerol.
d. What might limit the production of biodiesel to less than the calculated
amount?
e. Which type of biorefinery is this?
15.5
A company producing cola wants to increase the production of
”
made of PET (polyethylene terephthalate). Therefore, they plan to build a
plant to produce ethylene glycol (one of the two monomers of PET) from
sugarcane residues (bagasse). The capacity will be 500 kt.year
−1
.
“
green bottles
a. Make a block process diagram of how this biorefinery could look like.
b. Give the main reactions taking place in the process leading to ethylene
glycol.
c. How much bagasse (kt.year
−1
) would be needed in this process when
bagasse is assumed to consist of 38 wt% cellulose (db), 27 wt% hemicel-
lulose, 20 wt% lignin, 3 wt% proteins, 9 wt% extractives (water soluble),
and 3 wt% ash. Consider ethanol to be an intermediate product, which is
only made from the cellulose part via enzymatic hydrolysis and subsequent
sugar fermentation.
d. Which products can be made from the noncellulosic part of bagasse?
Search WWH ::
Custom Search