title: High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.
abstract: In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants.
authors.affiliation: Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. daVinci 32, 20133 Milano, Italy. Electronic address: laura.biganzoli@mail.polimi.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Biganzoli
authors.affiliation: Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. daVinci 32, 20133 Milano, Italy.
authors.forename: Gaia
authors.initials: G
authors.lastname: Racanella
authors.affiliation: Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. daVinci 32, 20133 Milano, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Rigamonti
authors.affiliation: Unicalce S.p.A., R&D Department, Via Tonio da Belledo 30, 23900 Lecco, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Marras
authors.affiliation: Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. daVinci 32, 20133 Milano, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Grosso
mesh_terms: D065966:Absorption, Physicochemical; D000393:Air Pollutants / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry; D017745:Incineration; D008274:Magnesium / Q000737:chemistry*; D013458:Sulfur Dioxide / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D005740:Gases; D013458:Sulfur Dioxide; D002119:Calcium Carbonate; D008274:Magnesium; D006851:Hydrochloric Acid; D006858:Hydrofluoric Acid; C028042:calcium magnesium carbonate
keywords: Acid gases; Depurcal®MG; Dolomitic sorbent; Waste-to-energy