Method for the purification of flue gas, filter system therefor, and retrofit unit

A method of purifying flue gas with a filter system, the method comprising:

• providing a filter unit having a housing, a filtering separator in said housing, the housing having a prefilter side upstream of the filtering separator in a flow direction and a clean side downstream of the filtering separator;
• providing a filter element being a filter cartridge configured for insertion into and extraction from the housing;
• delivering the flue gas to the filtering separator in the housing;
• injecting an adsorbent into the flue gas upstream of the filtering separator for causing part of the pollutants to be adsorbed by the adsorbent upstream of the filtering separator;
• with the filter cartridge inserted in the housing, conducting the flue gas through the filter element having a filter element adsorbent with dust-free spheroidal activated charcoal disposed on the clean side of the housing, the flue gas flowing from the filtering separator through the dust-free spheroidal charcoal in the filter element uniformly over its area, for separating out of the flue gas pollutants selected from the group consisting of mercury, dioxin, furan, and further heavy metals;
• preseparating part of the pollutants in a preseparator unit arranged outside the housing and/or preseparating part of the pollutants by way of the filtering separator, so that residual pollutants and pollutant quantities occurring with peak values are separated out of the flue gas by the filter element adsorbent;
• providing a gassing unit disposed between the filtering separator and the filter element and subjecting the filter element adsorbent to compressed gas for generating motion in the material of the adsorbent.