Balance concentration is generally brackets , the pure liquid balance concentration can be considered 1.
One unit weak acid and weak alkali solution, with Hac as an example, the total concentration is C , in the aqueous solution HAC Presented in HAC and AC -:
c = [HAC] + [AC-] or C = C (HAC) + C (AC -)
balance constant calculation:
aa (g ) + bb (g) === a certain condition === EE (g) + DD (g) k = [e] ^ E * [D] ^ D / [A] ^ a * [b] ^ b
Using the energy consumption analysis generated by solid product, add amendment in a conventional thermodynamic balance formula, calculating the HCL gas in a dry purification process using a lime absorbent. The equilibrium concentration, the first proposal of the equilibrium concentration of the reaction gas during the increase of the solid reaction rate increases. The calculation results show that after the absorbent reaches a certain reaction rate, the equilibrium concentration of the HCl decreases with the rise of the temperature. Some of the experimental phenomenon that the conventional thermodynamic balance cannot be explained using a variation of the reaction rate and temperature, and the equilibrium concentration can be utilized to predict the purification efficiency of HCl in the exhausting cooler of calcium-based absorbent dry purification incinerator. And the amount of absorbent. The prediction result can judge the range, limitations and improved direction of dry purification.
Factors affecting HCl balance concentration
First, it is necessary to clear that when the required push is large, δ g ' will increase (The absolute value is reduced), and the HCl balance concentration is elevated. As the absorber reaction rate x rose, the equilibrium concentration of HCl rises because the absorbent has a certain reaction rate, and the HCl needs to penetrate the product layer to the reaction surface, the concentration of HCl in the gas stream and the reaction surface HCl There must be a difference between the concentration, that is, the main gas flow and the reaction surface are in the reaction surface, the larger the reaction rate x, the thicker the product layer, the larger the partial pressure difference, and the product generation required Increased, so the balance concentration of HCl in the airflow increases with x rise. Next, in the range of 200 ~ 310 ° C, when X is increased, the balance concentration of HCl increases with the rise of temperature; when X is higher, the balance concentration of the HCl decreases with the rise of the temperature. This is because the temperature rises when the temperature rises, the value of the free enthalpy Δ g c increases the balance concentration, but since the grain diameter D increases, the product The multi-aperture, diffusion resistance is reduced, and the pressure difference of HCl is reduced; and according to equations, the pushing work required is also reduced. On the other hand, the total surface energy and the surface energy are also reduced, so the total free enthalpy δ g 'decreases with the rise of the temperature, so that the balance concentration of the HCl is lowered. . Third, when the pressure of the water vapor is raised, the balance concentration of the HCl is increased. Fourth, when X is zero or very small, CA (OH 2 ) corresponding to the HCl equilibrium concentration is higher than CAO, and when X is higher (for example x ≥ 15%), the HCl equilibrium concentration corresponding to the CaO will rise soon, and the temperature is lower than the CA (OH) 2 . Fifth, under the conditions of the same reaction rate, the modified lime corresponds to the HCl equilibrium concentration than the equilibrium concentration corresponding to the ordinary CA (OH) 2 .
HCl Balance Concentration Figure of Explanation of Experiments
The above change characteristics of the HCl balance concentration can explain some experimental phenomena. Under normal conditions, the chemical reaction of I and II is large, δ g c small, the positive reaction trend is strong, press δ g < Sub> C= 0 The calculated HCl balance concentration is very low, for example at 250 ° C and P H2O = 8%, using CA (OH) < Sub> 2and CaO as an absorbent, press δ g c = 0, the calculation balance concentration of HCl is below 0.1 × 10 -6, respectively, respectively and 0.001 × 10 -6 . However, the actual situation is: when 250 ° C and P H2O = 8%, the equivalent of the absorbent is 3 times the HCl of the absorbent in the limitations of the reaction time. It is difficult to reduce the concentration of HCl in flue gas to 80 × 10 - 6 , because the actual equilibrium concentration corresponding to the reaction rate is higher than 80 × 10 - 6 g c value of I, II is increased, and the reaction is reduced, but the ability to absorb the ability in the experiment The increase in temperature is improved, because the temperature rise HCl balance concentration decreases.
calculates the thermodynamic data of 4 sodium silicon slaves based on a linear relationship that constitutes a similar compound thermodynamics and composition, and calculates sodium aluminate. The relationship between the balance of silica after sodium silicon dollars and the temperature or caustic comparison is formed in the solution. The calculation results show that the calculation value of the silica balance concentration is consistent with the experimental value; at the same time, as the temperature increases or the caustic ratio increases, the silica balance concentration in the sodium aluminate solution increases.
Balance concentration calculation results with experimental results
According to sodium silica slag (set to NA 2 o al < Sub> 2o 3 . 2SIO 2 . 2h 2 O) The calculated value of the thermodynamic data, combined with the reaction equation of generating sodium silica slag, can calculate the balance concentration of silica when the sodium silicon slag is formed, and the calculation results are better than the CressW Ell and Hewett experimental results. It also illustrates sodium silica slag having a fixed structure, and its silica balance concentration increases with the increase of temperature, which is consistent with the experimental results.
Under the same conditions, the silica balance concentration formed after forming three sodium silica slag was calculated, and it was shown that the resulting sodium silicon slag 1, 4 was consistent with the HEW ETT experiment. Further, sodium silicon slag 2 is consistent with the results of Adamson, Leiteizen and Oku. That is, under different conditions, different sodium silicon slags are generated, which is illustrated in the balance concentration of silica, which is consistent with the generation of sodium silicon silica slag. The calculated sodium silica residue thermodynamic data is reliable.
The relationship between silica balance concentration and caustic is compared with temperature.
The caustic ratio is a molecular ratio of sodium oxide and alumina (记 为 为 K ) is a technical parameters commonly used in alumina production, calculating the relationship between forming silica equilibrium concentration and caustic ratio after forming three sodium silica.
The concentration of the silica increases with the increase of the caustic ratio of the solution, and as the temperature increases, the silica equilibrium concentration is increased, and it reaches an extreme at 200 ° C. value. These calculations were consistent with the experimental results.
The balance concentration of silica
(1) calculates the thermodynamic data of four sodium silicon slaves based on the composition of similar compound thermodynamic data and composition existing.
(2) The silica balance concentration is calculated in the sodium silicate solution, and the calculated value of the silica equilibrium dioxide concentration is consistent with the experimental value; at the same time, as the temperature increases or The increase in caustic ratio is increased in the sodium aluminate solution.