Process for the adsorption of toxic sulphur bearing gases
View Patent ↗The preparation of nano-oxide coated adsorbent, which is useful for treatment of toxic gases, by coating of composite materials containing hydrotalcite over ceramic monolithic substrates. Oxides and salts of metals are reacted in a known manner to prepare hydrotalcites or mixed metal layered hydroxides such as Mg—Al, Ca—Al, Zn—Al, Zn—Cr type possessing positive layer charge, from which a stable gel is prepared by adding swellable clay, e.g., montmorillonite etc. in different hydrotalcite:clay ratio in an aqueous medium and homogenizing the same with high speed homogenizer and ultrasonicator in a high intensity ultrasonic processor. The gel is dip-coated over cordierite/mulite honey-comb monolithic supports. The dip-coated monoliths are dried and calcined to develop the alumino-silicate supported nano-oxide coats over honey-comb ceramic substrates for carrying out adsorption of H 2 S and SO 2 gas in a He flow in various flow rates at 400 to 1000° C. temperature in a cylindrical quartz tube.
1. A process for the adsorption of toxic sulphur bearing gases using mixed metal oxidic nano sheets coated ceramic monolithic absorbent and the said process comprising the steps of:
i. providing mixed metal oxidic nano sheets coated ceramic monolithic absorbent by known method;
ii. passing toxic sulphur bearing gases over the absorbent as provided in step (i) at a flow rate of 5 to 50 ml/min at a space velocity in the range of 4.51 to 1628 hr −1 for period in the range of 20 minutes to 3 hours to remove 98.8 to 99.9% toxic gases.
2. The process as claimed in claim 1 , wherein toxic sulphur bearing gases are selected from SO 2 or H 2 S along with, He, Ar or N 2 or combination thereof.
3. The process as claimed in claim 1 , wherein adsorption of SO 2 is carried out at a temperature in the range of 600-850° C.
4. The process as claimed in claim 1 , wherein adsorption of H 2 S is carried out at a temperature in the range of 400-600° C.
5. The process as claimed in claim 1 , wherein the said starting oxides after adsorption of toxic gases are regenerated after heat treatment at moderately high temperature in the range of 500 to 1000° C. in presence of air and steam.
6. The process as claimed in claim 1 , wherein reaction area, length and diameter of cylindrical quartz reactor is in the range of 20-80 cm 3 , 10-60 cm and 2-3 cm respectively.
7. The process as claimed in claim 1 , wherein Specific Desulphurisation Efficiency (SDE) is in the range of 21,000 to 62,438, where SDE is the percentage desulphurization per weight of the active adsorbent component present in the composite (%/g).