Method and arrangement for optimizing oxidation during burning of gaseous and liquid fuels
AssigneeKvaerner Pulping AB
InventorsAri Tamminen, Risto Syrjalainen, Heikki Koivuniemi, Erkki Valimaki
Life of this patent
Estimating the term…
Abstract
A method and an arrangement for reducing emissions of nitrogen oxides in a combustion apparatus provided with a tubular furnace. The method comprises burning odor gases at first sub-stoichiometrically, and subsequently supplying additional air to the furnace (3) in the transverse direction thereof in such a manner that the final air ratio is over 1. The arrangement comprises an additional air duct (7) which extends to the furnace of the boiler and from which additional air is supplied to the furnace (3) in the transverse direction of the furnace (3).
Claims17
A method for reducing emissions of nitrogen oxides upon burning of odor gases of a pulp mill in a combustion apparatus provided with a tubular furnace, which has first and second opposite ends and a tubular wall between said first and said second opposite ends and which defines a longitudinal direction and transverse directions, said method comprising
- supplying odor gases, as fuel, and combustion air to the combustion apparatus from said first end of the furnace,
- and discharging the resulting flue gases from said second end of the furnace,
- wherein said combustion air is supplied sub-stoichoimetrically to the furnace of the combustion apparatus simultaneously with the odor gases to reduce the formation of nitrogen oxides,
- and wherein additional air is supplied at one or more points to a middle region of the furnace of the combustion apparatus from the middle of the furnace towards the walls through a separate duct which extends into the furnace from said second end wherein the total amount of said additional air and said combustion air corresponds at least to stoichiometric combustion.
An arrangement for reducing the amount of nitrogen oxides formed during combustion when odor gases of a pulp mill are burnt in a combustion apparatus provided with a tubular furnace, which has first and second opposite ends and a tubular wall between said first and said second ends and which defines a longitudinal direction and transverse directions,
- said arrangement comprising a fuel channel for supplying odor gases, as fuel, to said first end of the furnace,
- a combustion air duct for supplying combustion air to the furnace with the odor gases to said first end,
- and a discharge opening for discharging flue gases from said second end of the furnace,
- wherein said arrangement further comprises a separate additional air duct which extends into the furnace from said second end and which is arranged to supply additional air substantially to a middle region of the furnace and transversely at one or more points within the furnace from the middle of the furnace outwards.
Dependencies are inferred from the claim text.