Methanol synthesis from industrial CO2 sources

Methanol Synthesis from Industrial CO2
Sources: A Contribution to Chemical Energy
Conversion
DONE BY:
KISHAN KASUNDRA
Technical Seminar on:

CONTENTS
Introduction
Case study 1
Case study 2
Conclusion
references
6/15/2018 CHEMICAL ENGINEERING DEPARTMENT,DSCE 2

INTRODUCTION
The green-house effect is caused by the release of carbon dioxide into the atmosphere from
different power and chemical plants.
Conversion of CO2 to methanol is recognized as one of the most promising processes to reduce
the atmospheric CO2 level.
Moreover, using methanol as a fuel allows one to reduce the emissions of undesirable toxic
products such as unburned hydrocarbon, CO and NOx.
Methanol is used extensively in the plastics industry and also as solvents in the pharmaceutical
industry.

Based on reaction mechanisms of the CO/CO2/H2 conversion to methanol, three overall reactions
(Bussche and Froment, 1996) occur over Cu/ZnO/Al2O3 catalysts:
(1) Methanol decomposition: CO + 2H2 ↔ CH3OH
(2) Water shift gas: CO2 + H2 ↔ CO + H2O
(3) Methanol steam reforming: CO2 + 3H2↔ CH3OH + H2O
In addition to reactions (1), (2) and (3), other two reactions may occur (Eliasson et al., 1998):
(4) CO2 + 4H2 ↔ CH4 + 2H2O
(5) CO + 3H2 ↔ CH4 + H2O
Reactions (4) and (5) indicate that methane formation is the main obstacle limiting the production
methanol.

CASE STUDY -1: An analysis of methanol production route via CO2
hydrogenation by Rita M. B. Alves, Camila F. R. Machado
Figure 1: CO2 hydrogenation

Figure 2: Process flowsheet for direct CO2 to methanol Process

RESULTS:
Table presents simulation results concerning the utilities consumption per ton of methanol:
Consumption/ton of methanol d-CTM
Vapour (ton/ton) 1.26
Cooling water(m3/ton) 101.18
Electricity (GJ/ton) 3.36
Reactor conditions: T = 245 °C, P = 80 bar

Table shows the relevant factors of production for the d-CTM processes as methanol yield,
consumption of H2 and CO2, and CO2 emission
Factor d-CTM
Methanol Production 464kta
H2 consumption 99.04kta
CO2 consumption 664.8kta
Syngas consumption -
CO2 emission 19.02 ton CO2eq/h

Case d-CTM:
In this case, the influence of pressure and H2/CO2 (N ratio) on the following parameters were
investigated:
(1) Methanol production in kg/h
(2) CO2 conversion
(3) Selectivity to MeOH
(5) Water production in kg/h

Figure 3: different behaviours of (a)CO2 conversion, (b)selectivity to MeOH,(c) MeOH production and
(d)water production for a set of N ratios and pressures

Table: Behaviour of MeOH production, MeOH selectivity, CO2 conversion and water production due the
variation of pressure and N parameter of the d-CTM process

CASE STUDY 2: Methanol production route via synthesis gas by Olah,
George A. Beyond
Figure 4: Synthesis gas

Figure 5: Process flowsheet for syngas CO2 to methanol Process

RESULTS:
Table presents simulation results concerning the utilities consumption per ton of methanol:
Consumption/ton of methanol sg-CTM
Vapour (ton/ton) 0.30
Cooling water(m3/ton) 67.93
Electricity (GJ/ton) 1.34
Reactor conditions: T = 245 °C, P = 80 bar

Table shows the relevant factors of production for the sg-CTM processes as methanol yield,
consumption of H2 and CO2, and CO2 emission
Factor sg-CTM
Methanol Production 464kta
H2 consumption -
CO2 consumption -
Syngas consumption 536 kta
CO2 emission 15.56 ton CO2eq/h

Case sg-CTM
In this case, the influence of pressure and M ratio(H2-CO2/CO+CO2) on the following parameters
were investigated:
(1) Methanol production in kg/h.
(2) CO2 conversion.
(3) Selectivity to MeOH
(4) CO conversion

Figure 6: different behaviours of (a)methanol production, (b)CO conversion, (c)methanol selectivity
and (d)CO2 conversion for a set of M ratios and pressures

Table: Behaviour of CO conversion, CO2 conversion, MeOH selectivity and MeOH production due
the variation of pressure and M parameter of the sg-CTM process

CONCLUSION:
There are at least two paths for methanol synthesis using syngas or a mixture of H2 and CO2 as
raw material.
d-CTM process presents more consumption of utilities as vapor, cooling water and electricity
per ton of methanol production compared to sg-CTM.
d-CTM process emits 19.02 ton CO2 equivalent per hour against an emission of 15.56 ton CO2
equivalent per hour for sg-CTM.
Regarding the consumption of raw material, d-CTM process is more demanding compared to
sg-CTM .
The production of methanol through the sg-CTM process is maximized at high M parameter
but in the studied pressure range remains unchanged.

REFERENCES:
Turton, R., Bailie, R.C., Whiting, W.B., Shaeiwitz, J.A., 2016. Analysis, Synthesis, and Design
of Chemical Processes, third ed. Prentice Hall, Upper Saddle River, New Jersey
Olah, George A. Beyond, Oil and Gas:The Methanol Economy,Angew.Chem., Int. Ed., 44, 2017
Behrens M., Felix, Kasatkin I., Kühl S., Hävecker M., Abild-Pedersen F., Zander S., Girgsdies
F., Kurr P.,Kniep B., Tovar M., Fischer R. W.,Nørskov J. K.,Schlögl R.,The Active Site of
Methanol Synthesis over Cu/ZnO/Al2O3, Industrial Catalysts, vol. 336, 18 may, 2017

THANK YOU

Methanol synthesis from industrial CO2 sources

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