Semi-dry Desulfurization

Semi-dry desulphurization process


     Flue gas enters the absorption tower from the air distributor at the bottom of the fluidized bed to fully mix with lime hydrate grains. SO2,SO3 and other harmful gases such as HCI and HF then react with lime hydrate to produce Ca SO3.1/2H2O


Reaction mechanism:


      When the process water is atomized in the reactor after passing through the double fluid atomization nozzle, given full contact with flue smoke, cooled and humidified, calcium hydroxide powder particles will produce dry powder product after reaction with H2O、SO2、H2SO3. The whole reaction can be divided into three states of air, liquid and solid:









Process introduction:


     The flue gas from the boiler enters the reactor from the bottom and blends with the absorbent which enters the reactor from the air trough and the recycled ash from bag dust removal in around Venturi tube. After the washing of jet stream in the Venturi tube, the flue smoke, absorbent and ash enter the straight tube of the reactor after full blending. There’s a sprinkler at the flaring exit of the Venturi tube to reduce the gas temperature of the desulfuration tower to about 15 ℃ higher than the flue gas dew point with the atomized water from the sprinkler. On the condition of lower temperature and higher humidity, SO2 in the flue gas reacts with the absorbent to produce calcium sulfite and calcium sulfate. The treated flue gas enters the bag dust remover with lots of dry solid grains to be treated. Then the dry recycled ash will be separated from the flue gas by the bag dust remover to be transferred by the conveyer device to the reaction device to be recycled again. The temperature of the cleaned flue gas will not be lower than 15℃-its dew point, and it will be discharged into the chimney by the draught fan without being heated.




Characteristics of semi-dry desulphurization technology:



Process schematic drawings


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