1. Membrane Contactors for Dissolution of CO2 in water
P. V. Marakkar Kutty, Sourja Ghosh*, S Dasgupta, Sibdas Bandyopadhyay
Ceramic Membrane Division, Central Glass and Ceramic Research Institute (CSIR),
196 Raja S.C. Mullick Road, Jadavpur, Kolkata , India
1. Introduction
Dissolution of carbon dioxide in to sea water is considered as one of the avenues for CO2 sequestration in order to promote protection of the global environment. The solubility of CO2 in water depends on several factors like pressure and temperature of CO2 which are in equilibrium with the water, concentration of ionic solutes in water, pH, etc. The reaction mechanisms [3] facilitates dissolution of CO2 in water are given below.
It is needed to explore dissolution characteristics CO2 in water. The objective of this work is to explore the feasibility of increasing solubility of CO2 in water using ceramic membrane based contactor.
3. Results and discussion
Characteristics of water from different sources were analyzed and results are shown in Table 1. CO2 absorption at different contact time using different types of water are shown in figure 2a, 2b,2c. Variation of pH with time are shown in figure 2d. Variation of conductivity with time are shown in figure 2e and effect of mineral concentration rate of absorption of CO2 are shown in figure 2f.
Table .1 Characteristics of water from different sources
CO2(g) CO2(aq)
CO2(aq) +H2O H2CO3(aq)
H2CO H+ + HCO3-
Water from different sources
Conductivit y
[µS/cm]
Turbidity
[NTU] pH
TDS
[mg/l] Na
[ppm] K Ca Mg
Milli-Q water
2.02
0.18
5.9
1.0
N D
Tap water
170
3.36
6.9
85.0
17.2
2.84
35.99
8.85
Lake water
239
2.00
7.4
119.8
112
6.17
13.69
9.37
River water
998
0.75
7.27
663
179
129.03
241.65
548.92
Sea water
31287
0.53
5.25
20403
10556
380
400
1272
HCO H+ + CO32-
2. Experimental
Water samples collected from different sources were characterized with pH, TDS, conductivity, turbidity, alkalinity, etc, chemical constituents are determined by AAS (Model No Perkin Elmer 5100PC ). The schematic flow diagram for the gas-liquid contactor is shown in Fig 1. Water was pumped through the gas liquid contactor module made of 3nos of monochannel porous ceramic tube [6.7mm id/10.32mm od/132mm l/internal surface area mm2]. The CO2 gas [15%/N2, 20%/N2,and 100%] was passed through shell side of the module. Samples during reaction were collected at different time intervals and pH, TDS, conductivity, turbidity, alkalinity, etc were measured. Amount of CO2 absorbed was determined by estimation of HCO3- by titrating with sodium hydroxide solution using phenolphthalein as indicator[1].
N D = Non Detectable
Figure 2a. Absorption of CO2 by various
water with time from 100 % CO2
Figure 2b. Absorption of CO2 by various
water with time from 20 % CO2 in N2 5 10 15 20 25 30 40 60 80
100
120
Time in minute
Milli gram of CO 2
/litre of water
B Milli-Q water/15% co2
C Tap water/15% co2
D Lake water/15% co2
E River water/15% co2
F Sea water/15% co2
Membrane Contactor
Absorbent tank
Mixer
Gas outlet
CO2 N2 Air
Figure 2c. Absorption of CO2 by various
water with time from 15 % CO2 in N2
Figure 2d. Variation of pH of different water
with time during the experiment
Figure 1. Schematic flow diagram
Figure 2e Variation of conductivity of different
water with time during the experiment
Figure. 2f Effect of amount minerals
[Ca + Mg + Na +K] on rate of absorption of CO2
4. Conclusion
Among the various source of water used, tap water shows maximum CO2 absorption efficiency.
5. Reference
[1] Text Book “Arthur I. Vogal’s Quantitative Inorganic Analysis” Third Edition 1961.
Experimental setup
Poster Presented at International Symposium on Energy Materials: Opportunities and Challenges (ISEM-2011) March 1-2, 2011, CGCRI, Kolkata