Chemistry Reference
In-Depth Information
4.5 Small Hydrocarbon Storage
Small hydrocarbons (C
1
, C
2,
and C
3
) are important energy sources and chemical
feedstock in the petrochemical industry. In order to fully utilize these light hydro-
carbons, it is essential to have high quality and purity of such basic chemicals;
thus, separations of these light hydrocarbons are important industrial processes.
In general, to obtain high-purity single-component gas product, purification of
the small hydrocarbons is achieved using cryogenic distillation, which is a high
energy consumption process.
The pressure swing adsorption (PSA) process is a cost-effective and highly effi-
cient technique for separating small hydrocarbons [
60
-
62
]. In the PSA process,
the separation efficiency basically depends on the adsorption properties of solid
adsorbents. Thus, extensive efforts have been made to expand efficient solid adsor-
bents for PSA technology. Typically, PSA is carried out under kinetic dynamic
conditions and run a cycle in several minutes. To solve this challenge, the adsor-
bent must possess fast separation ability. Porous solid materials, such as zeolites,
and activated carbons have been examined for storage and separations of these
light hydrocarbons. However, these traditional adsorbents exhibit a low separation
capacity and selectivity in the process of separating small hydrocarbons mixtures.
Therefore, development of new adsorbents is required. MOFs have been exploited
as a new type of sorbents for hydrocarbon separation [
63
-
66
]. Compared with
MOFs, the new family of porous material, POFs have been documented as new
carriers for gas capture and storage [
1
-
3
]. Because of their controllable pore
connectivity, chemical tailorability, high stability, and large adsorption capac-
ity, POFs have emerged as appropriate candidates for small hydrocarbons storage
(Table
4.5
). Compared with utilization of POFs in the field of H
2
, CO
2
, and CH
4
storages, studies on small hydrocarbons are relatively rare.
Mercouri et al. reported the synthesis of mesoporous polymeric organic frame-
works (mesoPOF) using surfactant mediated polymerization of phlorglucinol
(1,3,5-trihydrox-ybenzene) and terephthalaldehyde under solvothermal conditions
(Fig.
4.12
a) [
67
]. The mesoPOFs present high surface areas up to 1,000 m
2
g
−
1
, and
their pore sizes range from micropores to large mesopores depending on the amount
Table 4.5
Small hydrocarbons storage in POFs
Materials
S
BET
(m
2
/g)
T
(K)
P
(bar)
CH
4
uptake
(cm
3
/g)
C
2
H
4
uptake
(cm
3
/g)
C
2
H
6
uptake
(cm
3
/g)
C
3
H
8
uptake
(cm
3
/g)
References
MesPOF-1
1,027
273
1
~18
57
[
67
]
MesPOF-1
902
~9
~33
[
67
]
548
~7
~24
[
67
]
MesPOF-1
Zn-CTF-400
1,411
298
1
11
70
112
[
68
]
Zn-CTF-500
1,848
298
1
15
90
161
[
68
]
1,331
298
1
9
54
103
[
68
]
Zn-CTF-600
MCOF-1
874
298
1
9
36
44
55
[
69
]
