Washing of gases in columns - with high liq. flow rates and increased efficiency

摘要

Washing of gas streams to remove gaseous or solid components is carried out by passing upwards through a plate column with at least one perforated or grid plate with free space ratio Fc (hole or slot area as a proportion of total area) of 0.30-0.60. Gas flow rate per unit column area (Ug) lies between a min. valve (Ug min) and 8 m/s. Downward flow rate (L) of wash fluid is 10,000-250,000 kg/m2/h and ratio (L/G) of fluid and gas flow rates is 0.5 min. Min. gas flow (Ug min) is defined by 6 equations for perforated plates and 6 equations for grid plates, and depends on liq. flow rate (L), free space ratio (Fc), flow ratio (L/G), gas/liq. density ratio (Pg/Pl/, and capillary constant (l). Used for removal of harmful gas and/or solid components, e.g. oxides of N and S, and dust, from exhaust gases acid gases and/or ammonia from coke oven gas, cooling of hot gases, etc. Liquid flow rates of 110,000-250,000 kg/m2/h. can be used, against 9,000-110,000 kg/m2/h. in known processes, without a rapid increase in pressure gradient across the column. Large gas vols. can be washed more efficiently and economically in relatively small columns.