Process maintains smoke gases at or above dew point after combustion of fossil fuels

摘要

Hot crude gas charged with pollutants is cooled by apparatus including a crude-gas cooler (3) in the path of flow of the crude-gas stream (1) between an electrostatic filter (2) and a gas scrubber (6) for withdrawing sulphur from the crude gas. A pure-gas heater (8) is incorporated in the pure-gas stream (7) between the scrubber (6) and a chimney (9). The crude-gas cooler (3) and the pure-gas heater (8) are coupled via a cooling fluid conveyed in a closed circuit (11). The heat-transmitting surfaces in the crude-gas cooler (3) are so dimensioned, in relation to the quantity and speed of the crude gas, that in each region of the crude-gas cooler (3) the crude gas conveyed in indirect counter-current to the cooling fluid has a temperature at or above the saturation curve defined by the specific dew-point temperature in the SO 3 /{C temperature graph. By this means, the formation of sulphuric acid aerosols can be prevented, or any sulphuric-acid aerosols formed can be separated from the crude gas.