126
X. Li et al.
an ultraviolet spectrophotometer to determine the defluorination and desulfurization
rates.
Experimental Method
In this paper, the relationship between pH value and CO 2 concentration can be
obtained by Eq. 1 [12, 13].
Y =
(H
+
) + X −
K H 2 O
(H + )
K 1 K 2 + K 1 (H
+
) + (H
+
)
2
2K 1 K 2 + K 1 (H + )
(1)
where: Y is the CO 2 concentration at any time, X is the initial NaOH solution concentration, K H2O , K 1, and K 2 are equilibrium constants (at 25 °C, K H2O = 10
–14 , K 1 =
10
–6.352 , K 2 = 10
–10.329 ).
According to the double-membrane theory and chemical reaction kinetics, the
total mass transfer rate equation can be expressed by Eq. 2, and the volumetric mass
transfer coefficient AK can be used to express the absorption rate.
ln[(Ce − Ct)/(Ce − C 0 )] = −(AK /V )t
(2)
where: A—reaction surface area, cm
2 ; V —the volume of NaOH solution, cm
3 ; t—
reaction time, s; K—mass transfer coefficient of CO 2 , cm/s; Ce, Ct, Co—respectively,
represent the equilibrium concentration of CO 2 , the concentration of CO 2 absorbed
by the NaOH solution after t seconds and the initial concentration of CO 2 , mol/L.
The utilization rate of CO 2 gas in the solution can be expressed as Eq. 3.
η = [V (C C O 2 I I − C C O 2 I )/t]/[ρ C O 2 Q/M]
(3)
where: C CO2II —CO 2 concentration in solution at t II , mol/L; C CO2I —CO 2 concentration in solution at t I , mol / L; t—Difference between t II and t I , s;— CO 2 gas density,
1.997 g/L; Q—CO 2 gas flow rate, L/s; M—CO 2 molecular weight, 44 g/mol.
The initial concentration of the NaOH solution used in this experiment was
0.025 mol/L. The main purpose of this experiment was to investigate the utilization of CO 2 η in the process of changing the pH value from 12 to 9. The formula
used in this experiment can be simplified as Eq. 4.
η = 6.45/Qt
(4)
X. Li et al.
an ultraviolet spectrophotometer to determine the defluorination and desulfurization
rates.
Experimental Method
In this paper, the relationship between pH value and CO 2 concentration can be
obtained by Eq. 1 [12, 13].
Y =
(H
+
) + X −
K H 2 O
(H + )
K 1 K 2 + K 1 (H
+
) + (H
+
)
2
2K 1 K 2 + K 1 (H + )
(1)
where: Y is the CO 2 concentration at any time, X is the initial NaOH solution concentration, K H2O , K 1, and K 2 are equilibrium constants (at 25 °C, K H2O = 10
–14 , K 1 =
10
–6.352 , K 2 = 10
–10.329 ).
According to the double-membrane theory and chemical reaction kinetics, the
total mass transfer rate equation can be expressed by Eq. 2, and the volumetric mass
transfer coefficient AK can be used to express the absorption rate.
ln[(Ce − Ct)/(Ce − C 0 )] = −(AK /V )t
(2)
where: A—reaction surface area, cm
2 ; V —the volume of NaOH solution, cm
3 ; t—
reaction time, s; K—mass transfer coefficient of CO 2 , cm/s; Ce, Ct, Co—respectively,
represent the equilibrium concentration of CO 2 , the concentration of CO 2 absorbed
by the NaOH solution after t seconds and the initial concentration of CO 2 , mol/L.
The utilization rate of CO 2 gas in the solution can be expressed as Eq. 3.
η = [V (C C O 2 I I − C C O 2 I )/t]/[ρ C O 2 Q/M]
(3)
where: C CO2II —CO 2 concentration in solution at t II , mol/L; C CO2I —CO 2 concentration in solution at t I , mol / L; t—Difference between t II and t I , s;— CO 2 gas density,
1.997 g/L; Q—CO 2 gas flow rate, L/s; M—CO 2 molecular weight, 44 g/mol.
The initial concentration of the NaOH solution used in this experiment was
0.025 mol/L. The main purpose of this experiment was to investigate the utilization of CO 2 η in the process of changing the pH value from 12 to 9. The formula
used in this experiment can be simplified as Eq. 4.
η = 6.45/Qt
(4)