The Effects Of Organic Impurities On The SO₂ Absorption And Desorption Properties Of HPP Aqueous Solution And Study On The Desulphurization Performance Of HPP Blends

The aqueous solution of organic amine has been used in removing sulfur dioxide from flue gas, which have the advantages of excellent absorption selectivity for SO2, high desulfurization efficiency, no secondary pollution and regeneration of absorption solution.SO2 in simulated flue gas was absorbed with the dynamic absorption in a packed tower and absorbents were regenerated by direct heating. The effects of organic impurities such as piperazine (PIP), N-(2-hydroxypropyl) piperazine,1,2-propanediol in the absorbent and CO2 in the inlet gas on the absorption and desorption performance of SO2 into aqueous l,4-bis(2-hydroxypropyl) piperazine (HPP) were investigated. Results indicated that piperazine is not conducive to the absorption and desorption of SO2. A small amount of N-(2-hydroxypropyl) piperazine and 1,2-propanediol have no influences on the saturated absorption capacity and the desorption rate of HPP to SO2. When the inlet gas contains CO2, the absorption and desorption performance of HPP is almost unchanged, HPP has a good absorption selectivity for SO2. The types of packing have almost no effects on the performance of the HPP for the SO2 removing under the experimental conditions.The absorption and desorption performance of PIP-HPP and methyldiethanolamine (MDEA)-HPP blends were compared with that of HPP. It was found that either the absorption rate or the saturated absorption capacity decreases with the addition of PIP or MDEA. With the pH adjusted by H2SO4,the first saturated absorption capacity decreases, the desorption rate increases, the second absorption capacity and desorption rate is basically same as that of the blended amine solutions with the pH value unchanged.CO2 has almost no effects on the absorption rate of the blended amine solutions, but it affects the saturated absorption capacity. In the presence of CO2, the saturated absorption capacity reduces with the pH adjusted by H2SO4, but it increases slightly with the pH value unchanged.