A desulfurization and denitrification agent and application thereof are provided, belonging to the fields of flue gas purification and purified product recycling. In the present disclosure, an imidazoline amine oxide is used as a desulfurization and denitrification agent, which can oxidize NO.sub.x and SO.sub.x into HNO.sub.3 and H.sub.2SO.sub.4. Meanwhile, after the agent is reduced, double bonded tertiary nitrogen atoms in the agent can be used as a base for neutralizing H.sub.2SO.sub.4 and HNO.sub.3. In addition, in the present disclosure, the imidazoline amine oxide is used as the desulfurization and denitrification agent for two-stage desulfurization and denitrification of flue gas. Waste liquid produced after the reaction is injected as foaming acid liquid into carbonate and tight sandstone reservoirs, and slowly hydrolyzed into H.sub.2SO.sub.4, HNO.sub.3, and HF at the reservoir temperature, and the produced acid reacts with the reservoirs to augment production and injection of the reservoirs.

A method and a filter device for the dry filtration of a gas flow carrying foreign objects in a filter device for purifying waste gas produced in additive manufacturing technologies, conducting a raw gas flow containing foreign objects into a raw gas space of a filter unit having at least one filter surface separating a raw gas side from a clean gas side, feeding oxidant to a reaction region located on the raw gas side of the filter surface downstream of the filter surface, such that foreign objects contained in material cleaned off from the filter surface and/or in the raw gas flow react with the oxidant in the reaction region to form foreign objects containing oxides.