Method for the treatment of gases, ellipsoidal packing and its use

Abstract

A method for treating a gas stream to remove heat, gaseous, liquid or particulate matter, or add heat, vapor, or moisture, which includes the steps of: providing a tower having a bed with fluidizable hollow ellipsoidal packing with a long semi-axis and a short semi-axis; introducing a liquid stream into the tower at a liquid flow rate L, and countercurrently introducing the gas stream into the tower at a gas flow rate G sufficient to maintain the bed in a fluidized state and a gas velocity v; and adjusting the volume ratio of the liquid flow to gas flow to cause the ellipsoidal packing to circulate predominantly in the vertical direction relative to the long semi-axis and to maintain a pressure gradient ΔP/H o across the depth of the fluidized bed of at least about 1500 Pa/m, and, simultaneously, to satisfy the equation: L/G=K.sub.1 (ΔP/H.sub.o v)+K.sub.2 wherein L/G is the volume ratio of liquid to gas; ΔP is the pressure drop across the bed; H o is the bed height in a state of rest; v is the gas velocity; and K 1 and K 2 are constants.

We claim: 
     
       1. A method for treating a gas stream to remove one or more of heat or gaseous, liquid or particulate constituents of said stream or to add heat, vapor or moisture to said stream, the method comprising the steps of: providing a tower having a bed comprising fluidizable hollow ellipsoidal packing having a long semi-axis and a short semi-axis;   introducing a liquid stream into said tower, said liquid in said stream having a liquid flow L;   countercurrently introducing said gas stream into said tower, said gas stream having a gas flow G sufficient to maintain said bed in a fluidized state and a gas velocity v;   adjusting the volume ratio of said liquid flow to said gas flow (L/G) to cause said ellipsoidal packing to be in a fluidized state and to circulate predominantly in the vertical direction relative to the long semi-axis and to maintain a pressure gradient ΔP/H o  across the depth of said fluidized bed of at least about 1500 Pa/m, and, simultaneously, to satisfy the equation:   L/G=K.sub.1 (ΔP/H.sub.o v)+K.sub.2     wherein     ΔP is the pressure drop across the bed;   H o  is the bed height in a state of rest;   v is the gas velocity; and   K 1  and K 2  are numerical constants.   
     
     
       2. The method of claim 1 wherein the volume ratio of said liquid flow to said gas flow, L/G, ranges from 0.001 to 0.01. 
     
     
       3. The method of claim 1 wherein the equation reads as follows:   ΔP/H.sub.o v=4.77+1.8(L/G)     wherein ΔP is in cm; H o  is in m; v is in m/sec; and L/G is the ratio of liquid to gas in dm 3  /m 3 .   
     
     
       4. The method of claim 1 wherein the ratio of the pressure gradient to the gas velocity is about 730 Pa/m/m/sec for a ratio of liquid to gas of between 0.001 and 0.002. 
     
     
       5. The method of claim 1 wherein the gas velocity is set at least at 1.75 m/sec in order to achieve a fluidized state and the fluidized state sets in at about 1,300 Pa/m, for an L/G of 0.001. 
     
     
       6. The method of claim 1 wherein said fluidized bed has a gas velocity of 1.15 m/sec, an L/G of 0.004 to 0.005, and a pressure gradient of 1,500 Pa/m. 
     
     
       7. The method of claim 1 wherein the ratio of the pressure gradient to the gas velocity is 1,300 Pa/m/m/sec at a gas velocity of 1.15 m/sec and a liquid to gas ratio of 0.004 to 0.005. 
     
     
       8. The method of claim 1 wherein at least one of the following gaseous materials: H 2  S, Cl 2 , SO 2 , HCl, HF, NH 3 , CO 2 , or water is removed from said gas stream. 
     
     
       9. The method of claim 1 wherein particulate impurities are removed from said gas stream, said method comprising an L/G of 0.001 to 0.003 for particle sizes greater than 1 μm and an L/G of 0.003 to 0.01 for particle sizes smaller than 1 μm. 
     
     
       10. The method of claim 1 wherein an exchange of heat takes place between said gas stream and said liquid stream, wherein for a diameter of the tower of at least 0.3 m and a gas flow rate of 1 to 4.5 m/sec, an L/G of 0.001 to 0.01 is employed. 
     
     
       11. The method of claim 1, wherein L/G ranges from 0.001 to 0.01. 
     
     
       12. The method of claim 1 wherein: ΔP/H o  v=1300 Pa/m 2 .s when L/G=0.004 to 0.005.