| 摘要 |
<PICT:1103859/C1/1> SO2 is removed from flue gases by passing them through a reactor having a plurality of independent compartments containing a porous bed of catalyst which accelerates the oxidation of SO2 to SO3. The reactor has duct means for directing the flue gases through the compartments and a means for selectively isolating one or more of the compartments to enable purging gas to be passed into the isolated compartment so as to re-activate the catalyst while passing the flue gases through at least some of the remaining compartments. As shown in Fig. 2, SO2-containing flue gases, after passing through an electrostatic dust precipitator (38), see Fig. 1 (not shown), enter the cylindrical reactor through duct 72 and pass through those radially spaced cells 52 containing catalyst which are not isolated by hood members 82, 84. The cells 52 have highly perforated walls. The treated flue gases leave via duct 74. Hood members 82, 84 of sectorial cross-section rotate about shaft 91 fitted with a slip-joint 93 and thus are able to isolate a radial set of cells. The purging gas passes through duct 89, the lower hood 84, the isolated cells, the upper hood 82 and out through duct 88. The particulate catalyst is retained in the cells 52 by valve 56. When this valve is opened the catalyst falls through hood 84 to duct 70 which is closed by a removable plate 76. After closing valve 56, as shown in the drawing, further catalytic material, e.g. V2O5, can be admitted to the cells through tube 92 and a series of branch ducts 94. The purge gas can be supplied to the reactor through a preheater, e.g. so as to heat the catalyst to 700-750 DEG F. The purge gas can be recycled to the preheater or can be mixed with the flue gases before they enter the dust precipitator (38). A heat exchanger (36) for the treated flue gases also warms the combustion air that is passed to the furnace (32) providing the flue gases. The SO3 in the flue gases combines with water also in the flue gases to form H2SO4, this is collected in a mist precipitator (42). S-free gases are exhausted through a stack (44). |
