US4600561A — Method and device for separating harmful substanc…

Claim 1

Independent Claim 195 words

Method for the separation of a harmful substance from a flue gas, and especially from sulfur oxide containing combustion gas, in which (a) in a single absorption heat exchanger arrangement cooling and washing the flue gas is carried out simultaneously, with the flue gas being cooled below the dew point; (b) said cooling is carried out by external air in counter flow to the flue gas flow; (c) the flue gas is divided in its passage through the absorption heat exchanger arrangement into at least two parallel partial flows, of which the first flow is conducted through a first treatment zone and the second flow is conducted through a second treatment zone; (d) in the first treatment zone a first absorption liquid is introduced into the flue gas to effect extensive removal of said harmful substance from the flue gas while in the second treatment zone a second absorption liquid is introduced into the flue gas, precipitated harmful substance being soluble in said second absorption liquid; (e) the two treatment zones are cyclically exchanged; and (f) condensate obtained from the flue gas and the absorption liquid are guided in unidirectional flow through said heat exchanger.

Claim 2

Dependent Claim 195 words

Method for the separation of a harmful substance from a flue gas, and especially from sulfur oxide containing combustion gas, in which (a) in a single absorption heat exchanger arrangement cooling and washing the flue gas is carried out simultaneously, with the flue gas being cooled below the dew point; (b) said cooling is carried out by external air in counter flow to the flue gas flow; (c) the flue gas is divided in its passage through the absorption heat exchanger arrangement into at least two parallel partial flows, of which the first flow is conducted through a first treatment zone and the second flow is conducted through a second treatment zone; (d) in the first treatment zone a first absorption liquid is introduced into the flue gas to effect extensive removal of said harmful substance from the flue gas while in the second treatment zone a second absorption liquid is introduced into the flue gas, precipitated harmful substance being soluble in said second absorption liquid; (e) the two treatment zones are cyclically exchanged; and (f) condensate obtained from the flue gas and the absorption liquid are guided in unidirectional flow through said heat exchanger.

Claim 3

Dependent Claim 40 words

Method according to claim 1 wherein the first absorption liquid is lime water, calcium dioxide suspension, calcium carbonate suspension or a mixture thereof, and wherein the second absorption liquid is water and sulfuric acid from the flue gas dissolved therein.

Claim 4

Dependent Claim 25 words

Method according to claim 1 wherein pre-cooling of the flue gas to 40° C. to 60° C. is carried out by means of heat recovery.

Claim 5

Dependent Claim 21 words

Method according to claim 1 wherein the cleaned flue gas is mixed with said external air before discharge into the atmosphere.

Claim 6

Dependent Claim 21 words

Method according to claim 1 wherein flue gas which passes through the second treatment zone is returned into the washing cycle.

Claim 7

Dependent Claim 53 words

Method according to claim 1 wherein five sixths of the flue gas is treated with the first absorption liquid and one sixth of the flue gas is treated with the second absorption liquid, and wherein the first and second treatment zones are exchanged according to a switching cycle lasting one to four hours.

Claim 8

Dependent Claim 152 words

Method for separation of a harmful substance from a flue gas, and especially from sulfur oxide-containing combustion gas, in which (a) the flue gas is cooled, (b) the flue gas is divided into at least two parallel partial flows of which the first partial flow is passed through a first treatment zone constituted by at least one of a plurality of parallel connected absorption towers, and of which the second partial flow is passed through a second treatment zone constituted by at least one of said absorption towers not a part of said first zone, (c) for gas cleaning in said first treatment zone a first absorption liquid is introduced into the flue gas in that zone, while for cleaning of equipment surfaces of said second treatment zone a second absorption liquid is introduced into the flue gas in said second treatment zone, and (d) the two treatment zones are cyclically exchanged.

Claim 9

Dependent Claim 152 words

Method for separation of a harmful substance from a flue gas, and especially from sulfur oxide-containing combustion gas, in which (a) the flue gas is cooled, (b) the flue gas is divided into at least two parallel partial flows of which the first partial flow is passed through a first treatment zone constituted by at least one of a plurality of parallel connected absorption towers, and of which the second partial flow is passed through a second treatment zone constituted by at least one of said absorption towers not a part of said first zone, (c) for gas cleaning in said first treatment zone a first absorption liquid is introduced into the flue gas in that zone, while for cleaning of equipment surfaces of said second treatment zone a second absorption liquid is introduced into the flue gas in said second treatment zone, and (d) the two treatment zones are cyclically exchanged.

Claim 10

Dependent Claim 168 words

Apparatus for separation of a harmful substance, especially a sulphur oxide, from a flue gas stream, comprising: (a) an absorption heat exchanger having at least two parallel connected treatment zones adapted for the passage of flue gas therethrough, (b) means for furnishing flue gas to said heat exchanger, (c) means for supplying first and second absorption liquids respectively to the first and second treatment zones, said first absorption liquid being effective to clean said harmful substance substantially from said flue gas, said second absorption liquid being a solvent for a precipitate of said harmful substance formed upon cleaning with said first absorption liquid, (d) means for cyclically exchanging said first and second treatment zones to supply alternately in each zone said first absorption liquid and said second absorption liquid, and (e) means for flowing external air over said first and second treatment zones of said heat exchanger, in counterflow to said flue gas, to cool said flue gas during passage of said flue gas through said heat exchanger.

Claim 11

Dependent Claim 168 words

Apparatus for separation of a harmful substance, especially a sulphur oxide, from a flue gas stream, comprising: (a) an absorption heat exchanger having at least two parallel connected treatment zones adapted for the passage of flue gas therethrough, (b) means for furnishing flue gas to said heat exchanger, (c) means for supplying first and second absorption liquids respectively to the first and second treatment zones, said first absorption liquid being effective to clean said harmful substance substantially from said flue gas, said second absorption liquid being a solvent for a precipitate of said harmful substance formed upon cleaning with said first absorption liquid, (d) means for cyclically exchanging said first and second treatment zones to supply alternately in each zone said first absorption liquid and said second absorption liquid, and (e) means for flowing external air over said first and second treatment zones of said heat exchanger, in counterflow to said flue gas, to cool said flue gas during passage of said flue gas through said heat exchanger.

Claim 12

Dependent Claim 18 words

Apparatus according to claim 8 wherein said second treatment zone comprises one sixth of the heat exchanger arrangement.

Claim 13

Dependent Claim 29 words

Apparatus according to claim 9 wherein said means for cyclic exchange of the treatment zones is operable to effect such exchange at time intervals of one to four hours.

Claim 14

Dependent Claim 15 words

Apparatus according to claim 8 wherein the heat exchanger comprises a plurality of parallel pipes.

Claim 15

Dependent Claim 14 words

Apparatus according to claim 11 wherein the pipes of the heat exchanger extend vertically.

Claim 16

Dependent Claim 29 words

Apparatus according to claim 12 wherein said supply means includes spray nozzles for the absorption liquids arranged above an entry for the flue gas into the heat exchanger pipes.

Claim 17

Dependent Claim 34 words

Apparatus according to claim 11 wherein the pipes of the heat exchanger are arranged within an annular area and the pipes within a plurality of sectors are combined together to form one operational zone.

Claim 18

Dependent Claim 37 words

Apparatus according to claim 8 wherein said supply means includes for each treatment zone a respective supply system for absorption liquid, which system can be switched from said first to said second absorption liquid and vice versa.

Claim 19

Dependent Claim 76 words

Apparatus according to claim 15 wherein each supply system comprises condensate collection means arranged beneath an exit of the heat exchanger, a receiving container connected to receive condensate from the collection means, a lime water container connected to supply lime water to the receiving container via a metering arrangement, pH measuring means for measuring the pH value of liquid from said receiving container, and spray nozzle means for spraying absorption liquid into the corresponding operational zone.

Claim 20

Dependent Claim 20 words

Apparatus according to claim 8 wherein the heat exchanger has a flue gas stack passing centrally of a tube bundle.

Claim 21

Dependent Claim 50 words

Apparatus according to claim 17 wherein at a flue gas outlet of each zone two alternately closable openings are provided, one opening providing a connection to the flue gas stack and the other opening providing a connection via a bypass line and a blower to said flue gas furnishing means.

Claim 22

Dependent Claim 54 words

Apparatus according to claim 8 wherein said supply means includes a spray nozzle arrangement for spraying the first absorption liquid to both treatment zones and further spray nozzle arrangement for spraying the second absorption liquid to either of said treatment zones, selectively, and for preventing entry of first absorption liquid into the selected zone.

Claim 23

Dependent Claim 57 words

Apparatus according to claim 8 wherein a flue gas stack passes outside a pipe bundle of the heat exchanger and wherein a tube is provided centrally of the pipe bundle, said tube being rotatable about an axis and carrying a spray nozzle arrangement for the second absorption liquid, the spray nozzle arrangement being supplied via said tube.

Claim 24

Dependent Claim 56 words

Apparatus according to claim 8 wherein said heat exchanger comprises a bundle of vertical pipes, and wherein beneath an outlet of the heat exchanger a condensate collecting body is provided which rotates together with a rotatable tube disposed centrally of the pipe bundle, whereby said collecting body is adjustable for location beneath the second treatment zone.

Claim 25

Dependent Claim 25 words

Method according to claim 1 wherein the partial flow to said first treatment zone is larger than the partial flow to said second treatment zone.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-07-14	1990-01-13	1990-07-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-07-14	1994-01-13	1994-07-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-07-14	1998-01-13	1998-07-15	$7700.00	Window Closed / Lapsed

Method and device for separating harmful substances from a flue gas

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