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US 4,509,436 AGranted
Method of and apparatus for the desulfurization of flue gas of a coal-fired combustion process
AssigneeOsterreichische Draukraftwerke Aktiengesellschaft
InventorsHerbert Schrofelbauer, Josef Kakl, Gernot Staudinger, Hermann Filipot
Life of this patent
Estimating the term…
Abstract
Flue gas from a coal-fired combustion to which a dry sulfur-binding additive is supplied, after cooling is subjected to filtration to remove additive ash therefrom. According to the invention, cooled additive ash is fed to at least a portion of the flue gas to reduce the temperature thereof approximately to the water dewpoint, thereby promoting the sulfur-binding reaction.
Claims13
A method of desulfurizing a raw gas generated by the combustion of coal in a combustion chamber, said method comprising in combination:
- (a) introducing into said combustion chamber a solid sulfur-binding additive adapted to form an additive ash which is entrained in said raw gas;
- (b) cooling a quantity of additive ash previously recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to form a cold additive ash;
- (c) cooling at least a portion of said raw gas to reduce the temperature thereof to a temperature level above a water dewpoint thereof at which water spontaneously condenses with lowering of temperature;
- (d) filtering at least said portion of said raw gas cooled in step (c) to recover additive ash therefrom, thereby forming a clean gas;
- (e) discharging said clean gas;
- and
- (f) further cooling at least said portion of said raw gas to substantially said dewpoint following step (c) and prior to step (d) by adding to it said portion of the additive ash cooled in step (b).
4 more elements
A method of desulfurizing a raw gas generated by the combustion of coal in a combustion chamber, said method comprising in combination:
- (a) introducing into said combustion chamber a solid sulfur-binding additive adapted to form an additive ash which is entrained in said raw gas;
- (b) cooling a quantity of additive ash previously recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to form a cold additive ash;
- (c) cooling at least a portion of said raw gas to reduce the temperature thereof to a temperature level above a water dewpoint thereof at which water spontaneously condenses with lowering of temperature;
- (d) filtering at least said portion of said raw gas cooled in step (c) to recover additive ash therefrom, thereby forming a clean gas;
- (e) discharging said clean gas;
- and
- (f) further cooling at least said portion of said raw gas to substantially said dewpoint following step (c) and prior to step (d) by adding to it said portion of the additive ash cooled in step (b), said raw gas being divided into two partial streams, a first of said partial streams subjected to steps (d), (e) and (f), the second of said partial streams being subjected to hot filtration to reduce a hot gas which is mixed with said clean gas prior to the discharge thereof so that the resulting mixture has a temperature enabling discharge thereof through a stack.
4 more elements
A method of desulfurizing a raw gas generated by the combustion of coal in a combustion chamber, said method comprising in combination:
- (a) introducing into said combustion chamber a solid sulfur-binding additive adapted to form an additive ash which is entrained in said raw gas;
- (b) cooling a quantity of additive ash previously recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to form a cold additive ash;
- (c) cooling at least a portion of said raw gas to reduce the temperature thereof to a temperature level above a water dewpoint thereof at which water spontaneously condenses with lowering of temperature;
- (d) filtering at least said portion of said raw gas cooled in step (c) to recover additive ash therefrom, thereby forming a clean gas;
- (e) discharging said clean gas;
- and
- (f) further cooling at least said portion of said raw gas to substantially said dewpoint following step (c) and prior to step (d) by adding to it said portion of the additive ash cooled in step (b);
- (g) preliminarily filtering said raw gas prior to the cooling thereof in step (c);
- and
- (h) dividing the raw gas after the preliminary filtering thereof into a first stream which is subjected to steps (c), (d), (e) and (f) and a second stream which is filtered hot to form a hot gas, said hot gas being combined with said clean gas prior to the discharge thereof to form a gas mixture at a temperature enabling the discharge thereof through a stack.
7 more elements
A method of desulfurizing a raw gas generated by the combustion of coal in a combustion chamber, said method comprising in combination:
- (a) introducing into said combustion chamber a solid sulfur-binding additive adapted to form an additive ash which is entrained in said raw gas;
- (b) cooling a quantity of additive ash previously recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to form a cold additive ash;
- (c) filtering at least a portion of said raw gas to recover additive ash therefrom thereby forming a clean gas;
- (d) discharging said clean gas;
- and
- (e) further cooling at least said portion of said raw gas to substantially its water dewpoint prior to step (c) by adding to said portion of the cooled raw gas at least a portion of the additive ash cooled in step (b).
3 more elements
An apparatus for the desulfurization of a raw gas generated by the combustion of coal in a combustion chamber comprising in combination:
- means for introducing into said combustion chamber a solid sulfur-additive adapted to form an additive ash which is entrained in said raw gas;
- means for cooling a quantity of additive ash recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to produce a cold additive ash;
- means for cooling at least a portion of said raw gas to reduce the temperature thereof to a temperature level above water dewpoint thereof at which water spontaneously condenses with lowering of temperature;
- means for filtering at least said portion of said raw gas following the cooling thereof to recover additive ash therefrom thereby forming a clean gas;
- means for exchanging said clean gas;
- and
- means for adding at least to said portion of the cool raw gas at least a portion of the cooled additive ash for further cooling said portion of said raw gas to a temperature of substantially said dewpoint.
4 more elements
An apparatus for the desulfurization of a raw gas generated by the combustion of coal in a combustion chamber comprising in combination:
- means for introducing into said combustion chamber a solid sulfur-additive adapted to form an additive ash which is entrained in said raw gas;
- means for cooling a quantity of additive ash recovered from a flue gas and formed by reaction in a coal-fired combustion chamber to produce a cold additive ash;
- means for cooling at least a portion of said raw gas to reduce the temperature thereof to a temperature level above water dewpoint thereof at which water spontaneously condenses with lowering of temperature;
- means for filtering at least said portion of said raw gas following the cooling thereof to recover additive ash therefrom thereby forming a clean gas;
- means for exchanging said clean gas;
- means for adding at least to said portion of the cooled raw gas at least a portion of the cooled additive ash for further cooling said portion of said raw gas to a temperature of substantially said dewpoint;
- a preliminary filter for removing additive ash from said raw gas;
- means for dividing the raw gas downstream of said preliminary filter into two partial streams, one of said partial streams forming said portion;
- means for hot filtering the other of said partial streams to form a hot gas;
- and
- means for mixing said hot gas with said clean gas to form a gas mixture at a relative temperature for discharge through a stack.
8 more elements
Dependencies are inferred from the claim text.