165
Table 5 (continued)
Feedstock Process
Merits (a) and
demerits (b)
Operating
condition
Final yield of
propylene
Ethylene
and butene
Metathesis
(a) Suitable where
ethylene is abundant
severe condition
(b) Feedstock
specific, yields
depend on feedstock
purity
20–50 °C
(re-alumina
catalyst),
300–375 °C
90–95%
C4 to C10
olefins
Olefins interconversion
using proprietary
ZSM-5-based catalyst
(a) Operating and
investment cost is
low
(b) Yield is low
400–550 °C,
1–2 atm.
40–50%
Gas oil
Route-1: FCC unit
(FCCU) with
conventional operating
condition
(a) Operational
flexibility, propylene
yield can be tuned
using different
catalyst
(b) Catalyst
deactivation, large
CO 2 emission, low
grade propylene,
investment cost is
very high
500–600 °C,
1.7–2.4 atm.
For conventional
FCC: 4–7%,
FCC + ZSM-5:
7–10%
Route-2: FCCU with
high severity operating
condition in presence
of proprietary ZSM-5
zeolite additive
(a) Yield improved
over conventional
FCC
(b) High operation
cost and still
propylene purity
remains concern
>600 °C,
1.7 atm.
15–25%
Coal
Route-1: Gasification
of coal to syngas,
syngas to methanol
and MTP
(a) Matured
technology,
chemical grade
propylene, feedstock
flexibility
(b) Multiple steps,
endothermic SMR
and gasification for
syngas production
For MTO/MTP
process:
350–500 °C,
0.1–4 atm.
For OCP:
400–550 °C,
1–2 atm.
MTO for
propylene:
80–85%
Route-2: Gasification
of coal to syngas,
syngas to methanol,
MTO couple with
olefin cracking process
(OCP)
Natural
gas
Reforming to syngas,
methanol synthesis,
MTO with OCP
C3-Based Petrochemicals: Recent Advances in Processes and Catalysts