Novel eco-efficient reactive distillation process for dimethyl carbonate production by indirect alcoholysis of urea
Iulian Patrașcu1, Costin S. Bîldea1, Anton A. Kiss2()
1. Department of Chemical and Biochemical Engineering, University “Politehnica” of Bucharest, 011061 Bucharest, Romania 2. Department of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, UK
Dimethyl carbonate is an eco-friendly essential chemical that can be sustainably produced from CO2, which is available from carbon capture activities or can even be captured from the air. The rapid increase in dimethyl carbonate demand is driven by the fast growth of polycarbonates, solvent, pharmaceutical, and lithium-ion battery industries. Dimethyl carbonate can be produced from CO2 through various chemical pathways, but the most convenient route reported is the indirect alcoholysis of urea. Previous research used techniques such as heat integration and reactive distillation to reduce the energy use and costs, but the use of an excess of methanol in the trans-esterification step led to an energy intensive extractive distillation required to break the dimethyl carbonate-methanol azeotrope. This work shows that the production of dimethyl carbonate by indirect alcoholysis of urea can be improved by using an excess of propylene carbonate (instead of an excess of methanol), a neat feat that we showed it requires only 2.64 kW·h·kg–1 dimethyl carbonate in a reaction-separation-recycle process, and a reactive distillation column that effectively replaces two conventional distillation columns and the reactor for dimethyl carbonate synthesis. Therefore, less equipment is required, the methanol-dimethyl carbonate azeotrope does not need to be recycled, and the overall savings are higher. Moreover, we propose the use of a reactive distillation column in a heat integrated process to obtain high purity dimethyl carbonate (>99.8 wt-%). The energy requirement is reduced by heat integration to just 1.25 kW·h·kg–1 dimethyl carbonate, which is about 52% lower than the reaction-separation-recycle process. To benefit from the energy savings, the dynamics and control of the process are provided for ±10% changes in the nominal rate of 32 ktpy dimethyl carbonate, and for uncertainties in reaction kinetics.
. [J]. Frontiers of Chemical Science and Engineering, 2022, 16(2): 316-331.
Iulian Patrașcu, Costin S. Bîldea, Anton A. Kiss. Novel eco-efficient reactive distillation process for dimethyl carbonate production by indirect alcoholysis of urea. Front. Chem. Sci. Eng., 2022, 16(2): 316-331.
Almost complete conversion, small amounts pass through the DMC synthesis process and are recycled
PG
187.7
Recycle from DMC synthesis to PC synthesis
PC
241.8
Recycle, within the DMC synthesis process
Tab.2
Component i
Component j
Aij
Aji
Bij/°C
Bji/°C
MeOH
DMC
10.3134
–1.59695
–2999.76
547.54
MeOH
PG
0
0
1088.26
–478.899
PC
DMC
–13.0479
–18.6292
8171.48
7346.46
PG
DMC
0.785035
0.81429
50.1177
–4.81697
MeOH
PC
0
0
191.527
92.4028
PC
PG
0.547578
0.948968
0.688674
0.490589
NH3
DMC
0
0
–1086.99
2923.74
NH3
MeOH
42.312
7.06459
–12020.9
–2887.41
NH3
PC
0
0
–1129.71
3183.35
NH3
PG
1.17657
–2.1687
0
0
Tab.3
Fig.2
Fig.3
Fig.4
Fig.5
Fig.6
Fig.7
Fig.8
Fig.9
Scenario
Energy balance
Total
Savings
Conv. DC
Unit
C1
C2
C3
C4
CSTR1&2
Energy/kW
237.3
5584.7
4722.8
3266.1
1585.1
15396
0%
Conv. HI-DC
Unit
C1
C2
C3
C4
CSTR1&2
Energy/kW
240.0
4790.6
714.4
3256.5
1585.5
10587
–31%
DC&RDC
Unit
C1
RDC
C2
Heat
CSTR1&2
Energy/kW
262.3
2100
2868.5
98
1593.4
6922
–55%
HI-DC&RDC
Unit
C1
RDC
C2
–
CSTR1&2
Energy/kW
262.5
1220
2847.4
–
747.3
5077
–67%
Tab.4
Item description (unit)
C1
RDC
C2
CSTR1&2
HEX
Cool
Mixer
V-L
Total
Shell/(103 US$)
26.4
172.2
417.0
425.3
196.9
210.5
298.0
201.5
1947.8
Internals/(103 US$)
1.2
87.4
48.9
–
–
–
–
–
137.6
Condenser/(103 US$)
26.1
77.7
139.4
–
–
–
–
–
243.1
Reboiler/(103 US$)
87.6
190.3
570.7
–
–
–
–
–
1043.3
Heating/(103 US$·year–1)
58.8
347.3
810.2
173.4
–
–
–
–
1389.7
Cooling/(103 US$·year–1)
1.7
8.5
41.9
–
–
12.5
–
10.4
75.0
TAC/(103 US$·year–1)
107.7
531.7
1244.1
315.1
65.6
82.7
99.3
77.6
2523.7
Tab.5
Fig.10
Controller
PV, value & range
OP, value & range
Kc/%
Time/min
FC urea
Flow rate= 2704 kg·h–1
LC mix PGMKUP
Level= 1.875 m
Flow rate PGMKUP= 32.9 kg·h–1
130
13.2
0–3.75 m
0–1000 kg·h–1
Ratio control
Flow rate urea= 2704 kg·h–1
Flow rate propilen glicol= 3581 kg·h–1
1.324
Concentration controller (CC) urea
Urea concentration= 1.429 wt-%
Urea:PG= 1.324
0.06
500
0.04–0.24 wt-%
0–2.64
TC CSTR1
Temperature= 180 °C
Heat duty= 2.33 GJ·h–1
5
6
130 °C–230 °C
−46–46 GJ·h–1
LC CSTR1
Level= 2.90 m
Product flow rate CSTR1= 6285 kg·h–1
10
60
0–4.14 m
0–12571 kg·h–1
TC CSTR2
Temperature= 180 °C
Heating duty= 0.35 GJ·h–1
5
6
130 °C–230 °C
−7–7 GJ·h–1
LC CSTR2
Level= 2.90 m
Flow rate product CSTR2= 5082 kg·h–1
10
60
0–4.14 m
0–10164 kg·h–1
TC flash V-L
Temperature= 50 °C
Cooling duty= −1.8 GJ·h–1
10
20
40 °C–60 °C
−3.6–0 GJ·h–1
LC flash V-L
Level= 1 m
Product flow rate= 5082 kg·h–1
10
60
0–2 m
0–10164 kg·h–1
PC flash V-L
Column pressure= 0.5 bar
Vapor flow rate= 70.4 kmol·h–1
20
12
0–1 bar
0–140 kmol·h–1
PC C1
Column pressure= 0.5 bar
Vapor flow rate= 20 kmol·h–1
20
12
0–1 bar
0–40 kmol·h–1
LC reflux drum C1
Level= 3.35 m
Flow rate reflux= 339.8 kg·h–1
94
2.64
0–4.8 m
0–679 kg·h–1
LC sump C1
Level= 0.61 m
Bottom flow rate= 4714.9 kg·h–1
10
60
0–1.22 m
0–9428 kg·h–1
TC stage 1 C1
Temperature= 94.44 °C
Condenser duty= −0.301 GJ·h–1
10
20
84 °C–104 °C
−1.89–0 GJ·h–1
TC stage 6 C1
Temperature= 195.2 °C
Reboiler duty= 0.944 GJ·h–1
10
20
185 °C–205 °C
0–1.89 GJ·h–1
TC Cool1
Temperature= 49 °C
Cooler duty= −2.16 GJ·h–1
5
1
39 °C–59 °C
−4.33–0 GJ·h–1
Ratio control
Flow rate PC= 15084.2 kg·h–1
Flow rate metanol= 2884.38 kg·h–1
0.1912
PC RDC
Column pressure= 1 bar
Condenser duty= −1.48 GJ·h–1
20
12
0–2 bar
−2.96–0 GJ·h–1
LC reflux drum RDC
Level= 1.37 m
Distillate flow rate= 4050.7 kg·h–1
10
60
0–2.75 m
0–8099.8 kg·h–1
LC sump RDC
Level= 1.43 m
Bottom flow rate= 13917.9 kg·h–1
10
60
0–2.85 m
0–27830 kg·h–1
TC stage 3 RDC
Temperature= 49.7 °C
PC:urea= 0.1912
0.0488
7.92
40 °C–60 °C
0–0.38
TC stage 33 RDC
Temperature= 149.79 °C
Reboiler duty= 4.39 GJ·h–1
10
20
140 °C–160 °C
0–8.78 GJ·h–1
PC C2
Column pressure= 0.25 bar
Top vapors flow rate= 178.56 kmol·h–1
20
12
0–5 bar
0–357.05 kmol·h–1
LC reflux drum C2
Level= 1.56 m
Condensate flow rate= 13665.38 kg·h–1
10
60
0–3.12 m
0–27325.32 kg·h–1
LC sump C2
Level= 1.875 m
Bottom flow rate= 10369.3 kg·h–1
10
60
0–3.75 m
0–20734.25 kg·h–1
TC condenser C2
Temperature= 145.97 °C
Condenser duty= −7.27 GJ·h–1
10
20
135 °C–155 °C
−14.53–0 GJ·h–1
TC stage 44 C2
Temperature= 179.66 °C
Reboiler duty= 10.25 GJ·h–1
10
20
?
170 °C–190 °C
0–20.5 GJ·h–1
Tab.6
Fig.11
Fig.12
1
P Tundo, M Selva. The chemistry of dimethyl carbonate. Accounts of Chemical Research, 2002, 35(9): 706–716 https://doi.org/10.1021/ar010076f
2
B A V Santos, V M T M Silva, M J Loureiro, A E Rodrigues. Review for the direct synthesis of dimethyl carbonate. ChemBioEng Reviews, 2014, 1(5): 214–229 https://doi.org/10.1002/cben.201400020
3
Z Huang, J Li, L Wang, H Jiang, T Qiu. Novel procedure for the synthesis of dimethyl carbonate by reactive distillation. Industrial & Engineering Chemistry Research, 2014, 53(8): 3321–3328 https://doi.org/10.1021/ie403964q
4
P Kongpanna, V Pavarajarn, R Gani, S Assabumrungrat. Techno-economic evaluation of different CO2-based processes for dimethyl carbonate production. Chemical Engineering Research & Design, 2015, 93: 496–510 https://doi.org/10.1016/j.cherd.2014.07.013
5
T Matsuzaki, A Nakamura. Dimethyl carbonate synthesis and other oxidative reactions using alkyl nitrites. Catalysis Surveys from Japan, 1997, 1(1): 77–88 https://doi.org/10.1023/A:1019020812365
6
A Sánchez, L M Gil, M. Martín Sustainable DMC production from CO2 and renewable ammonia and methanol. Journal of CO2 Utilization, 2019, 33: 521–531
7
L Shi, D J Wang, D S H Wong, K Huang. Novel process design of synthesizing propylene carbonate for dimethyl carbonate production by indirect alcoholysis of urea. Industrial & Engineering Chemistry Research, 2017, 56(40): 11531–11544 https://doi.org/10.1021/acs.iecr.7b02341
8
I Patrașcu, C S Bîldea, A A Kiss. Novel eco-efficient process for dimethyl carbonate production by indirect alcoholysis of urea. Chemical Engineering Research & Design, 2020, 160: 486–498 https://doi.org/10.1016/j.cherd.2020.06.020
9
M A Pacheco, C L Marshall. Review of dimethyl carbonate (DMC) manufacture and its characteristics as a fuel additive. Energy & Fuels, 1997, 11(1): 2–29 https://doi.org/10.1021/ef9600974
10
H Z Tan, Z Q Wang, Z N Xu, J Sun, Y P Xu, Q S Chen, Y Chen, G C Guo. Review on the synthesis of dimethyl carbonate. Catalysis Today, 2018, 316: 2–12 https://doi.org/10.1016/j.cattod.2018.02.021
11
H J Kuenen, H J Mengers, D C Nijmeijer, A G J van der Ham, A A Kiss. Techno-economic evaluation of the direct conversion of CO2 to dimethyl carbonate using catalytic membrane reactors. Computers & Chemical Engineering, 2016, 86: 136–147 https://doi.org/10.1016/j.compchemeng.2015.12.025
12
K Y Hsu, Y C Hsiao, I L Chien. Design and control of dimethyl carbonate-methanol separation via extractive distillation in the dimethyl carbonate reactive-distillation process. Industrial & Engineering Chemistry Research, 2010, 49(2): 735–749 https://doi.org/10.1021/ie901157g
13
S J Wang, C C Yu, H P Huang. Plant-wide design and control of DMC synthesis process via reactive distillation and thermally coupled extractive distillation. Computers & Chemical Engineering, 2010, 34(3): 361–373 https://doi.org/10.1016/j.compchemeng.2009.05.002
14
Q Li, S Zhang, B Ding, L Cao, P Liu, Z Jiang, B Wang. Isobaric vapor liquid equilibrium for methanol+ dimethyl carbonate+ trifluoromethanesulfonate-based ionic liquids at 101.3 kPa. Industrial & Engineering Chemistry Chemical & Engineering Data Series, 2014, 59: 3488–3494
15
H Matsuda, H Takahara, S Fujino, D Constantinescu, K Kurihara, K Tochigi, K Ochi, J Gmehling. Isothermal vapor-liquid equilibria at 383.15–413.15 K for the binary system methanol+ DMC and the pressure dependency of the azeotropic point. Fluid Phase Equilibria, 2019, 492: 101–109 https://doi.org/10.1016/j.fluid.2019.03.019
16
H P Luo, J H Zhou, W D Xiao, K H J Zhu. Isobaric vapor-liquid equilibria of binary mixtures containing DMC under atmospheric pressure. Journal of Chemical & Engineering Data, 2001, 46(4): 842–845 https://doi.org/10.1021/je0002639
17
T Mathuni, J I Kim, S J J Park. Phase equilibrium and physical properties for the purification of propylene carbonate (PC) and y-butyrolactone (GBL). Journal of Chemical & Engineering Data, 2011, 56(1): 89–96 https://doi.org/10.1021/je100803e
18
A Pyrlik, W Hoelderich, K Müller, W Arlt, J Strautmann, D Kruse. Dimethyl carbonate via transesterification of propylene carbonate with methanol over ion exchange resign. Applied Catalysis, 2012, B125: 486–491 https://doi.org/10.1016/j.apcatb.2011.09.033
19
J Holtbruegge, M Leimbrink, P Lutze, A Górak. Synthesis of dimethyl carbonate and propylene glycol by transesterification of propylene carbonate with methanol: catalyst screening, chemical equilibrium and reaction kinetics. Chemical Engineering Science, 2013, 104: 347–360 https://doi.org/10.1016/j.ces.2013.09.007
20
A C Dimian. Integrated Design and Simulation of Chemical Processes. Amsterdam: Elsevier, 2003
21
W L Luyben. Principles and Case Studies of Simultaneous Design. Hoboken: Wiley, 2011
22
A A Kiss. Advanced Distillation Technologies. Chichester: Wiley, 2013
