US4378977A — Removal of undesired gaseous components from hot …

Claim 1

Independent Claim 134 words

In a process for removing undesired gaseous components from hot combustion gases by scrubbing with a regenerable absorbent, the improvement comprising: conducting the scrubbing with a liquid physical absorbent at a temperature less than 0° C. and supplying required cooling of the scrubbing process by means of an absorption-type refrigeration unit, cooling the combustion gases prior to scrubbing, in indirect heat exchange with gas streams to be heated, the indirect heat exchange being performed in an upper temperature range and a subsequent lower temperature range, and using air as said gas stream to be heated in the upper temperature range of the indirect heat exchange, resultant heated air being used in part as (a) preheated air of combustion or in part as (b) an energy source for the operation of the absorption-type refrigeration unit.

Claim 2

Dependent Claim 134 words

In a process for removing undesired gaseous components from hot combustion gases by scrubbing with a regenerable absorbent, the improvement comprising: conducting the scrubbing with a liquid physical absorbent at a temperature less than 0° C. and supplying required cooling of the scrubbing process by means of an absorption-type refrigeration unit, cooling the combustion gases prior to scrubbing, in indirect heat exchange with gas streams to be heated, the indirect heat exchange being performed in an upper temperature range and a subsequent lower temperature range, and using air as said gas stream to be heated in the upper temperature range of the indirect heat exchange, resultant heated air being used in part as (a) preheated air of combustion or in part as (b) an energy source for the operation of the absorption-type refrigeration unit.

Claim 3

Dependent Claim 232 words

In a process for removing undesired gaseous components from hot combustion gases by scrubbing with a regenerable absorbent, the undesired gaseous components being passed through dessicators prior to removal from the system, and the scrubbed combustion gases being removed through an exhaust stack, the improvement comprising: conducting the scrubbing with a liquid physical absorbent at a temperature less than 0° C. and supplying the required cooling of the scrubbing process by means of an absorption-type refrigeration unit, cooling the combustion gases prior to scrubbing, in indirect heat exchange with gas streams to be heated, the indirect heat exchange being performed in an upper temperature range and a lower temperature range, and using air as said gas stream to be heated in the upper temperature range of the indirect heat exchange, resultant heated air being used in part as (a) preheated air of combustion, in part as (b) an energy source for the operation of the absorption-type refrigeration unit, in part as (c) an admixture to the purified combustion gases for increasing the temperature of the purified combustion gas and thus, the draft in the exhaust stack of the system, and for lowering the dew point of water in the flue gas, or in part as (d) a purging gas for regenerating the dessicators arranged for having the stream of products removed from the regenerated absorbent pass therethrough before removal from the system.

Claim 4

Dependent Claim 232 words

In a process for removing undesired gaseous components from hot combustion gases by scrubbing with a regenerable absorbent, the undesired gaseous components being passed through dessicators prior to removal from the system, and the scrubbed combustion gases being removed through an exhaust stack, the improvement comprising: conducting the scrubbing with a liquid physical absorbent at a temperature less than 0° C. and supplying the required cooling of the scrubbing process by means of an absorption-type refrigeration unit, cooling the combustion gases prior to scrubbing, in indirect heat exchange with gas streams to be heated, the indirect heat exchange being performed in an upper temperature range and a lower temperature range, and using air as said gas stream to be heated in the upper temperature range of the indirect heat exchange, resultant heated air being used in part as (a) preheated air of combustion, in part as (b) an energy source for the operation of the absorption-type refrigeration unit, in part as (c) an admixture to the purified combustion gases for increasing the temperature of the purified combustion gas and thus, the draft in the exhaust stack of the system, and for lowering the dew point of water in the flue gas, or in part as (d) a purging gas for regenerating the dessicators arranged for having the stream of products removed from the regenerated absorbent pass therethrough before removal from the system.

Claim 5

Dependent Claim 29 words

A process according to claim 1 or 2, wherein cold combustion gas purified by the scrubbing is used in the lower temperature range as said stream to be heated.

Claim 6

Dependent Claim 32 words

A process according to claim 3, wherein the temperature boundary between the upper and lower temperature range zones is above the temperature of the air used for cooling the hot combustion gases.

Claim 7

Dependent Claim 34 words

A process according to claim 3, wherein the heated air following its use as an energy source for the operation of the absorption cooling system, is mixed with the resultant purified, heated waste gas.

Claim 8

Dependent Claim 51 words

A process according to claim 1 or 2, wherein the absorption cooling system is operated with an ammonia-water mixture and the ammonia acting as the coolant cools both the regenerated absorbent, and the purified waste gas flowing from the head of the scrubbing column, and said ammonia coolant is evaporated thereby.

Claim 9

Dependent Claim 35 words

A process according to claims 1 or 2, further comprising a heat pump system, said system removing heat from at least the physical absorbent and transferring said heat to the coolant of the absorption system.

Claim 10

Dependent Claim 24 words

A process according to claim 7, wherein the absorption cooling system is operated by a water-ammonia mixture and the heat pump system by ammonia.

Claim 11

Dependent Claim 62 words

A process according to claim 8, wherein the ammonia of the heat pump system condensed by the evaporating ammonia of the absorption cooling equipment following expansion is evaporated in heat exchange against both (a) the absorbent to be cooled and to be fed into a scrubbing column, and (b) purified waste gas to be removed from the top of the scrubbing column.

Claim 12

Dependent Claim 19 words

A process according to claim 9, wherein the ammonia of the heat pump system is evaporated at sub-atmospheric pressure.

Claim 13

Dependent Claim 20 words

A process according to claim 3, wherein the heat exchange for cooling the combustion gas takes place in reversible regenerators.

Claim 14

Dependent Claim 27 words

A process according to claim 11, wherein separate regenerators are provided for each of the upper and the adjoining lower temperature range zones of the heat exchange.

Claim 15

Dependent Claim 62 words

A process according to claim 12, wherein each of the regenerators associated with the upper temperature range zone comprises two axially sequential packings separated by a partition, one of said packings always being traversed by the combustion gas to be cooled, and the other simultaneously by the air to be heated, and the packings being periodically reversed between combustion gas and air.

Claim 16

Dependent Claim 60 words

A process according to claim 12, wherein pairs of regenerators comprising axially sequential packings and periodically reversed between the flows of gases to be cooled and to be heated are used for the lower temperature range, the gases passing through the two packings of each particular regenerator always in opposite directions, either from the middle to the ends or vice-versa.

Claim 17

Dependent Claim 55 words

A process according to claim 14, wherein the regenerator of each pair fed with combustion gas precooled in the upper temperature range, is traversed from the middle to the ends and the other regenerator, fed with the cold purified combustion gas to be heated, is traversed from the ends to the middle by said media.

Claim 18

Dependent Claim 52 words

A process according to claim 3, for removing sulfur dioxide from combustion gases containing SO 2 , SO 3 and H 2 O and further comprising separating sulfuric acid formed during precooling in the upper temperature range zone for the precooled combustion gas before the latter enters the lower temperature range zone.

Claim 19

Dependent Claim 29 words

A process according to claim 16, wherein the combustion gases precooled in the upper temperature range zone of the heat exchange are compressed before entering the lower temperature range.

Claim 20

Dependent Claim 13 words

A process according to claims 1 or 2, wherein dimethylformamide is the absorbent.

Claim 21

Dependent Claim 29 words

A process according to claim 18, comprising regenerating the absorbent in two separate stages, codissolved carbon dioxide being expelled in the first stage and sulfur dioxide in the second.

Claim 22

Dependent Claim 31 words

A process according to claim 19, characterized in that the carbon dioxide is expelled by means of a stripping gas and the sulfur dioxide at sub-atmospheric pressure and with heat applied.

Claim 23

Dependent Claim 33 words

A process according to claim 18, further comprising removing any sulfur acid formed from residual H 2 O and residual sulfur trioxide or SO 3 from oxidized sulfur dioxide from the regenerated absorbent.

Claim 24

Dependent Claim 14 words

A process according to claim 21, wherein the sulfuric acid is removed by neutralization.

Claim 25

Dependent Claim 13 words

A process according to claim 22, wherein neutralization is carried out with ammonia.

Claim 26

Dependent Claim 14 words

A process according to claim 22, wherein the neutralization is conducted with calcium oxide.

Claim 27

Dependent Claim 15 words

A process according to claim 21, wherein dimethylformamide is separated from sulfuric acid by distillation.

Claim 28

Dependent Claim 28 words

A process according to claim 25, wherein residual dimethylformamide is removed from sulfuric acid concentrated by distillation by extracting the dimethylformamide with a solvent immiscible with sulfuric acid.

Claim 29

Dependent Claim 14 words

A process according to claim 26, wherein the solvent is a polar, organic solvent.

Claim 30

Dependent Claim 17 words

A process according to claim 27, wherein the extraction is carried out in the presence of water.

Claim 31

Dependent Claim 14 words

A process according to claim 27, wherein the solvent is chloroform, toluene, or benzene.

Claim 32

Dependent Claim 34 words

A process according to claim 1, further comprising removing any remaining moisture in undesired gaseous components removed from the regenerated absorbent by passing the undesired gaseous components through dessicators before removal from the process.

Claim 33

Dependent Claim 22 words

A process as in claim 2, wherein said resultant heated air is used only in part as (a) preheated air of combustion.

Claim 34

Dependent Claim 29 words

A process as in claim 2, wherein said resultant heated air is used only in part as (b) an energy source for the operation of the absorption-type refrigeration unit.

Claim 35

Dependent Claim 57 words

A process as in claim 2, wherein said resultant heated air is used only in part as (c) an admixture to the purified combustion gases for increasing the temperature of the purified combustion gas and thus, the draft in the exhaust stack of the system, and for lowering the dew point of water in the flue gas.

Claim 36

Dependent Claim 44 words

A process as in claim 2, wherein said resultant heated air is used only in part as (d) a purging gas for regenerating the dessicators arranged for having the stream of products removed from the regenerated absorbent pass therethrough before removal from the system.

Claim 37

Dependent Claim 110 words

A process as in claim 2, wherein said resultant heated air is used in part as (a) preheated air of combustion, in part as (b) an energy source for the operation of the absorption-type refrigeration unit, in part as (c) an admixture to the purified combustion gases for increasing the temperature of the purified combustion gas and thus, the draft in the exhaust stack of the system, and for lowering the dew point of water in the flue gas, and in part as (d) a purging gas for regenerating the dessicators arranged for having the stream of products removed from the regenerated absorbent pass therethrough before removal from the system.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-04-04	1986-10-04	1987-04-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-04-04	1990-10-04	1991-04-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-04-04	1994-10-04	1995-04-05	$7700.00	Window Closed / Lapsed

Removal of undesired gaseous components from hot waste gases

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag