Using lime we can:
- reduce the permeability of the filtering bags: the lime deposited in the interstices of the filtering surface prevents small particles from entering, thus increasing the efficiency of filtration;
- neutralize acid pollutants: thanks to its chemical characteristics, calcium hydroxide is suitable for the abatement of acid pollutants (HF, HCl and SO2) present inside the fumes to be purified. This feature is of fundamental importance as it also avoids the degradation of the filtering surface;
- protect the filter elements from any unburnt particles: we may find particles that have not completed the combustion process remaining dispersed in the air flow. These particles have a strong tendency to aggregate. Lime is able to avoid this behaviour and reduce the risk to damage filtering media (e.g. reduce fire risk).
This neutralizing process, therefore, led to a series of important advantages, but what are the fields of application?
As we have seen, it is used for the treatment of high temperature fumes that, for example, can be generated by biomass plants, thermoelectric power plants, incinerators and from the treatment of hazardous and non-hazardous waste.