CA1129181A - So.sub.2 scrubbing system for flue gas desulfurization - Google Patents
So.sub.2 scrubbing system for flue gas desulfurizationInfo
- Publication number
- CA1129181A CA1129181A CA347,516A CA347516A CA1129181A CA 1129181 A CA1129181 A CA 1129181A CA 347516 A CA347516 A CA 347516A CA 1129181 A CA1129181 A CA 1129181A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- water
- loop
- solids
- scrubbing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/48—Sulfur dioxide; Sulfurous acid
- C01B17/50—Preparation of sulfur dioxide
- C01B17/60—Isolation of sulfur dioxide from gases
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
II. ABSTRACT
Sulfur dioxide is scrubbed from boiler flue gases in a double-loop alkali scrubber, one a quencher loop and the other an absorption loop. The reagent flow of the two loops is cycled to the absorber loop and a portion of the make-up water for the quencher loop is received from the absorber loop. By controlling recycled water from a dewatering system and selective utilization of high and low solids streams from the absorber system, the quencher slurry concentration may be controlled and the requirement for new make-up water reduced.
Sulfur dioxide is scrubbed from boiler flue gases in a double-loop alkali scrubber, one a quencher loop and the other an absorption loop. The reagent flow of the two loops is cycled to the absorber loop and a portion of the make-up water for the quencher loop is received from the absorber loop. By controlling recycled water from a dewatering system and selective utilization of high and low solids streams from the absorber system, the quencher slurry concentration may be controlled and the requirement for new make-up water reduced.
Description
1l~918l FOR FLUE GAS DESULFURIZATION
.
I. DESCRIPTION
Technical Field This invention is directed to a unique double-loop S2 scrubbing system for flue gas desulfurization which optimizes use of make-up water while controlling slurry concentration for S02 scrubbing efficiency and quenching.
Background of Prior Art Scrubbing of boiler flue gases with slurries of limestone (CaC03) or calcine limestone products, lime and hydrated lime, is a kno~m method for the removal of sulfur dioxide (S02) from these combustion gases. The standard system does, however, require significant amounts of make-up water for operation and therefore increases the total plant requirements for water. As suitable quality water is often available to the plant only in limited quantities, it is essential that the scrubbing system use a minimum of high quality make-up or reused water.
Make-up water is required in sulfur dioxide scrub-bing systems to replace water lost principally in two areas:
~1) water lost through evaporation by the quenching and lowering the temperature of flue gases passing into the scrubber; and (2) water lost with the discharge of the solid waste product composed of a slurry of unreacted reagent, calcium sulfite hydrates and calcium sulfate hydrates that are discharged from the system. The total make-up water requirements for the system can, therefore, be minimized by reducing these water losses.
llZ9181 ~rief Summary of Invention Applicants have discovered that by controlling recycled water from a dewatering system and selective utilization of high and low solids streams from the absorber system, the quencher slurry concentration may be controlled and the requirement for new make-up water reduced. The two loop process isolates the main absorber system including the demisters; which are prone to scaling and corrosion, from the evaporative quencher portion of the process. All the recycled water is returned to the evaporative quencher loop and none to the loop containing the demisters and the primary absorber sections. However, under varying SO2 feed rates, the recycled water to the quencher loop may be in excess or insufficient for the evaporative material balance of the quencher loop. To compensate for either imbalance, it is necessary to utilize a separator and flow control between the two loops to decrease or increase the water balance Elow to the quencher loop while maintaining the absorber loop at the proper operating balance.
Normally, the slurry composition should be controlled to allow qreater than 3~ reaction products of combined calcium sulfite and calcium sulfate in the quencher loop. Further, to achieve an effective absorption of sulfur dioxide, the calcium base must be maintained above a minimum level. Typically, an absorber operates between 6% and 14% solid content.
The two loop process then, permits the operation of the demisters and the primary absorber sections in a complete open loop, whereupon contaminated recycled water is avoided and use of additional demister wash water is maximized.
Eliminating recycled water in these sections reduces the en-crustations, scale formation and uncontrolled crystallization which hampers continuous operation of the SO2 removal system.
This also permits the use of less expensive materials which would be required to prevent attack by dissolved chemicals such as chlorides.
The use of recycled water from the dewatering system in the second loop, namely the quencher section, permits the operation of the total system in a closed loop such that all the water available is utilized in the process rather than l~Z~181 being disposed.
~rief Description of Drawings The invention will be more particularly described in reference to the drawings wherein:
FIG. 1 is a simplified flow diagram of the system;
FIG. 2 is a partial sectional diagrammatic view of a multi-stage quencher-absorber tower useful for carrying out the system of the invention.
Detailed Description of Invention Referring to FIG. 1 of the drawings, 10 generally designates a system of the invention and the system includes a multiple-stage quencher-absorber tower 12, to be more fully described in reference to FIG. 2, which includes a quencher 14 and an absorber 16.
lS Arrows 18a, b and c designate, respectively, the gas flow to the quencher 14, gas flow from the quencher 14 to the absorber 16 and the SO2 stripped glue gas from the absorber 16.
Other primary components of the system include absorber tank 20, quencher tank 22, dewatering system 24, an absorber separator 26, pumps 28, 30, and 32, each of which has a pump seal water inlet designated 34a, b and c for pumps 32, 30 and 28 respectively.
The primary liquid/slurry lines for the system are:
line 36 from the absorber tank 20 to pump 28; line 38 com-prising the primary absorber feed line from the pump 28 to the absorber 16; secondary absorber feed line 40 from absorber tank 20 to pump 30; secondary absorber feed line 42 from pump 30 to absorber 16; line 44 comprising a branch of line 42 from the secondary absorber feed to the absorber separator 26; line 46 from the absorber 16 to the absorber tank 20, the demister wash water line 48 for the multi-stage quencher-absorber tower 12; line 50 the reagent feed line for absorber tank 20;
exit line 52 from the absorber separator 26 to absorber tank 20; exit line 54 from the absorber separator 26; absorber tank 20 overflow line 56 to the quencher tank 22; line 58 from quencher tank 22 to pump 32; line 60 comprising the quencher feed line from pump 32 to the quencher 14; quencher return line 62 from quencher 14 to the quencher tank 22; line 64 comprising the discharge from the quencher tank 22 to the dewatering system 24; line 66 from the dewatering system 24 to the quencher tank 22; and line 68 comprising the dewater-ing system blow down line from dewaterer 24.
Referring now to FIG. 2, the multi-stage quencher-absorber tower 12 has a vertically extending shell 70 with a flue gas inlet 72 adjacent at the lower and a SO2 stripped flue gas outlet 73 at the upper end. Below the flue gas inlet 72 is a sump 22 or quencher tank provided with a sump stirring mechanism generally designated 76.
In FIG. 2, the quencher section is generally desig-nated 14 and the absorber section is generally designated 16.The quencher section includes a plurality of headers 80, which would be connected to line 60 from the pump 32, with each of the headers being provided with a plurality of spray outlet nozzles 82. In a preferred embodiment, the quencher section 14 is of the cyclonic type as the flue gases entering inlet 72 are caused to flow tangentially upwardly. Return line 62 depicted in FIG. 1 is the return by gravity of the treating fluid from the headers 80 to the quencer tank 22.
Between the quencher section 14 and the absorber section 16 is a gas/liquid bowl separator generally designated 84. This separator 84 collects the water from the demister and the slurry fluid from the absorber and the collected fluid is directed from the separator 84 for return to the absorber tank, via line 46. Above the bowl separator 84 are a plural-ity of headers designated 86 and 86a each having connection tolines 38 and 42 comprising the primary and secondary absorber feed lines.
Each of the headers 86 and 86a is provided with a plurality of spray type outlet nozzles 88 and between the headers 86 and 86a is a conventional packed tower arrangement 90. Above the header 86a is arranged lower demister 92 and upper demister 94. Wash water for the lower demister is provided via header 96 having spray type outlets 98. The ~129181 upper demister 94 is also provided with a wash water means including a header 100 provided with spray type outlets 102.
The absorber separator 26 and the dewatering system 24 designated in FIG. 1 may take form of hydroclones, thickeners, centrifuges or vacuum filters.
Referring again to the drawings of the present invention, the two-loop system includes a auencher loop A
wherein almost all of the evaporative water losses occur, and an absorber loop B (which includes the demisters 92-94) wherein gases pass first through the quencher loop, then through the absorber loop. Reagent flow is counter-current to the gas flow, passing first through the absorber loop.
Solids are removed from the system as follows: Solids products of the reaction between the calcium based reagent and sulfur dioxide, as well as some unreacted reagent, are fed from the absorber tank 20 of the absorber loop B to the quencher loop A along with some water through line 56 at rather constant concentration. Slurry is also fed to loop A
by line 44, absorber separator 26 and line 54. The solids are then circulated through the quencher loop A wherein more reaction products are formed as the concentration of unreacted reagent decreases. The solids are then discharged from the quencher to the dewatering system 24 and ultimate waste disposal.
~ake-up water enters the absorber loop as tl) water entering with the reagent at 50; (2) small amounts of water for slurry pump packing glands at 34c and b; and (3) demister wash water at 48. ~ake-up water enters the quencher loop as:
(1) small amounts of fresh make-up water for slurry pump and agitator packing glands at 34a and 34d, respectively; (2) quencher make-up water (recycled water) at 66, which replaces most of the evaporative losses; and (3) water accompanying the absorber loop discharge solids at 56'.
When the process requirement for quencher make-up water is satisfied by the recycled water generated by the sludge dewatering system and the absorber loop discharge, optimum water utilization is achieved.
Where the recycled water generated exceeds the , ' ' , , ~Z9~8~
quencher make-up water requirement, the concentration of solids in the ~bsorber loop discharge slurry must be increased. ~his is accomplished by standard controls at the absorber separation 26 which directs the high solids stream S containing solids content in the range of 10% to 50% to flow through line 54 to mix with the slurry flowing through line 56 while the low solids stream containing solids content in the range of 3~ to 10% is to be returned to the absorSer tank 20. ~he absorber loop then operates as an open system dis-charging high solids content slurry into the quencher loop.Of course, both loops considered together constitute a closed loop system.
For those operating conditions when the recycled water generated is less than the quencher make-up water requirement, it is desirable to increase the water content or decrease the solids content in the absorber discharge by directing the low solids stream existing from the separator 26 to mix with the absorber tank discharge slurry in line 56'.
At the same time, water may be added to the absorber loop as demister wash water relative to the total fresh make-up water requirement.
As described above, it is necessary to vary the amount of water exiting with the absorber loop discharge solids, that is, the concentration of the discharge slurry, without affecting the solids and chemical balance of the absorber loop. This is done through the use of solid/liquid separating device 26 and controls which may be commercially purchased. This device treats a portion of the absorber loop slurry to generate two streams, a high solids stream and a low solids stream. Either or both of these streams can be combined through one or more lines 54 with an appropriate quantity of untreated absorber loop slurry 56 to produce a stream 56' containing the desired concentration in the slurry flowing into quencher tank 22. With this approach, a wide range of solids content is attainable from the absorber discharge stream.
Because plant operating conditions, i.e., load factor and S02 gas content, are constantly varying, the rate ~r, r , llZ9181 of solids generation in the absorber circuit, and the amount of water required to enter the quencher circuit are also changing. To allow the absorber system to react to the process requirements for water versus solids in the slurry a process signal is utilized. This siqnal relates the S02 mass flow into the absorber tower, absorber slurry density, or any other process variable which changes with changing S02 mass flow to the absorber tower to the required concentration of slurry discharge from the absorber loop to the quencher tank. The signal is fed to a controller (not show) which maintains the concentration of solids discharge to the quencher tank at the desired level.
i;
~,
.
I. DESCRIPTION
Technical Field This invention is directed to a unique double-loop S2 scrubbing system for flue gas desulfurization which optimizes use of make-up water while controlling slurry concentration for S02 scrubbing efficiency and quenching.
Background of Prior Art Scrubbing of boiler flue gases with slurries of limestone (CaC03) or calcine limestone products, lime and hydrated lime, is a kno~m method for the removal of sulfur dioxide (S02) from these combustion gases. The standard system does, however, require significant amounts of make-up water for operation and therefore increases the total plant requirements for water. As suitable quality water is often available to the plant only in limited quantities, it is essential that the scrubbing system use a minimum of high quality make-up or reused water.
Make-up water is required in sulfur dioxide scrub-bing systems to replace water lost principally in two areas:
~1) water lost through evaporation by the quenching and lowering the temperature of flue gases passing into the scrubber; and (2) water lost with the discharge of the solid waste product composed of a slurry of unreacted reagent, calcium sulfite hydrates and calcium sulfate hydrates that are discharged from the system. The total make-up water requirements for the system can, therefore, be minimized by reducing these water losses.
llZ9181 ~rief Summary of Invention Applicants have discovered that by controlling recycled water from a dewatering system and selective utilization of high and low solids streams from the absorber system, the quencher slurry concentration may be controlled and the requirement for new make-up water reduced. The two loop process isolates the main absorber system including the demisters; which are prone to scaling and corrosion, from the evaporative quencher portion of the process. All the recycled water is returned to the evaporative quencher loop and none to the loop containing the demisters and the primary absorber sections. However, under varying SO2 feed rates, the recycled water to the quencher loop may be in excess or insufficient for the evaporative material balance of the quencher loop. To compensate for either imbalance, it is necessary to utilize a separator and flow control between the two loops to decrease or increase the water balance Elow to the quencher loop while maintaining the absorber loop at the proper operating balance.
Normally, the slurry composition should be controlled to allow qreater than 3~ reaction products of combined calcium sulfite and calcium sulfate in the quencher loop. Further, to achieve an effective absorption of sulfur dioxide, the calcium base must be maintained above a minimum level. Typically, an absorber operates between 6% and 14% solid content.
The two loop process then, permits the operation of the demisters and the primary absorber sections in a complete open loop, whereupon contaminated recycled water is avoided and use of additional demister wash water is maximized.
Eliminating recycled water in these sections reduces the en-crustations, scale formation and uncontrolled crystallization which hampers continuous operation of the SO2 removal system.
This also permits the use of less expensive materials which would be required to prevent attack by dissolved chemicals such as chlorides.
The use of recycled water from the dewatering system in the second loop, namely the quencher section, permits the operation of the total system in a closed loop such that all the water available is utilized in the process rather than l~Z~181 being disposed.
~rief Description of Drawings The invention will be more particularly described in reference to the drawings wherein:
FIG. 1 is a simplified flow diagram of the system;
FIG. 2 is a partial sectional diagrammatic view of a multi-stage quencher-absorber tower useful for carrying out the system of the invention.
Detailed Description of Invention Referring to FIG. 1 of the drawings, 10 generally designates a system of the invention and the system includes a multiple-stage quencher-absorber tower 12, to be more fully described in reference to FIG. 2, which includes a quencher 14 and an absorber 16.
lS Arrows 18a, b and c designate, respectively, the gas flow to the quencher 14, gas flow from the quencher 14 to the absorber 16 and the SO2 stripped glue gas from the absorber 16.
Other primary components of the system include absorber tank 20, quencher tank 22, dewatering system 24, an absorber separator 26, pumps 28, 30, and 32, each of which has a pump seal water inlet designated 34a, b and c for pumps 32, 30 and 28 respectively.
The primary liquid/slurry lines for the system are:
line 36 from the absorber tank 20 to pump 28; line 38 com-prising the primary absorber feed line from the pump 28 to the absorber 16; secondary absorber feed line 40 from absorber tank 20 to pump 30; secondary absorber feed line 42 from pump 30 to absorber 16; line 44 comprising a branch of line 42 from the secondary absorber feed to the absorber separator 26; line 46 from the absorber 16 to the absorber tank 20, the demister wash water line 48 for the multi-stage quencher-absorber tower 12; line 50 the reagent feed line for absorber tank 20;
exit line 52 from the absorber separator 26 to absorber tank 20; exit line 54 from the absorber separator 26; absorber tank 20 overflow line 56 to the quencher tank 22; line 58 from quencher tank 22 to pump 32; line 60 comprising the quencher feed line from pump 32 to the quencher 14; quencher return line 62 from quencher 14 to the quencher tank 22; line 64 comprising the discharge from the quencher tank 22 to the dewatering system 24; line 66 from the dewatering system 24 to the quencher tank 22; and line 68 comprising the dewater-ing system blow down line from dewaterer 24.
Referring now to FIG. 2, the multi-stage quencher-absorber tower 12 has a vertically extending shell 70 with a flue gas inlet 72 adjacent at the lower and a SO2 stripped flue gas outlet 73 at the upper end. Below the flue gas inlet 72 is a sump 22 or quencher tank provided with a sump stirring mechanism generally designated 76.
In FIG. 2, the quencher section is generally desig-nated 14 and the absorber section is generally designated 16.The quencher section includes a plurality of headers 80, which would be connected to line 60 from the pump 32, with each of the headers being provided with a plurality of spray outlet nozzles 82. In a preferred embodiment, the quencher section 14 is of the cyclonic type as the flue gases entering inlet 72 are caused to flow tangentially upwardly. Return line 62 depicted in FIG. 1 is the return by gravity of the treating fluid from the headers 80 to the quencer tank 22.
Between the quencher section 14 and the absorber section 16 is a gas/liquid bowl separator generally designated 84. This separator 84 collects the water from the demister and the slurry fluid from the absorber and the collected fluid is directed from the separator 84 for return to the absorber tank, via line 46. Above the bowl separator 84 are a plural-ity of headers designated 86 and 86a each having connection tolines 38 and 42 comprising the primary and secondary absorber feed lines.
Each of the headers 86 and 86a is provided with a plurality of spray type outlet nozzles 88 and between the headers 86 and 86a is a conventional packed tower arrangement 90. Above the header 86a is arranged lower demister 92 and upper demister 94. Wash water for the lower demister is provided via header 96 having spray type outlets 98. The ~129181 upper demister 94 is also provided with a wash water means including a header 100 provided with spray type outlets 102.
The absorber separator 26 and the dewatering system 24 designated in FIG. 1 may take form of hydroclones, thickeners, centrifuges or vacuum filters.
Referring again to the drawings of the present invention, the two-loop system includes a auencher loop A
wherein almost all of the evaporative water losses occur, and an absorber loop B (which includes the demisters 92-94) wherein gases pass first through the quencher loop, then through the absorber loop. Reagent flow is counter-current to the gas flow, passing first through the absorber loop.
Solids are removed from the system as follows: Solids products of the reaction between the calcium based reagent and sulfur dioxide, as well as some unreacted reagent, are fed from the absorber tank 20 of the absorber loop B to the quencher loop A along with some water through line 56 at rather constant concentration. Slurry is also fed to loop A
by line 44, absorber separator 26 and line 54. The solids are then circulated through the quencher loop A wherein more reaction products are formed as the concentration of unreacted reagent decreases. The solids are then discharged from the quencher to the dewatering system 24 and ultimate waste disposal.
~ake-up water enters the absorber loop as tl) water entering with the reagent at 50; (2) small amounts of water for slurry pump packing glands at 34c and b; and (3) demister wash water at 48. ~ake-up water enters the quencher loop as:
(1) small amounts of fresh make-up water for slurry pump and agitator packing glands at 34a and 34d, respectively; (2) quencher make-up water (recycled water) at 66, which replaces most of the evaporative losses; and (3) water accompanying the absorber loop discharge solids at 56'.
When the process requirement for quencher make-up water is satisfied by the recycled water generated by the sludge dewatering system and the absorber loop discharge, optimum water utilization is achieved.
Where the recycled water generated exceeds the , ' ' , , ~Z9~8~
quencher make-up water requirement, the concentration of solids in the ~bsorber loop discharge slurry must be increased. ~his is accomplished by standard controls at the absorber separation 26 which directs the high solids stream S containing solids content in the range of 10% to 50% to flow through line 54 to mix with the slurry flowing through line 56 while the low solids stream containing solids content in the range of 3~ to 10% is to be returned to the absorSer tank 20. ~he absorber loop then operates as an open system dis-charging high solids content slurry into the quencher loop.Of course, both loops considered together constitute a closed loop system.
For those operating conditions when the recycled water generated is less than the quencher make-up water requirement, it is desirable to increase the water content or decrease the solids content in the absorber discharge by directing the low solids stream existing from the separator 26 to mix with the absorber tank discharge slurry in line 56'.
At the same time, water may be added to the absorber loop as demister wash water relative to the total fresh make-up water requirement.
As described above, it is necessary to vary the amount of water exiting with the absorber loop discharge solids, that is, the concentration of the discharge slurry, without affecting the solids and chemical balance of the absorber loop. This is done through the use of solid/liquid separating device 26 and controls which may be commercially purchased. This device treats a portion of the absorber loop slurry to generate two streams, a high solids stream and a low solids stream. Either or both of these streams can be combined through one or more lines 54 with an appropriate quantity of untreated absorber loop slurry 56 to produce a stream 56' containing the desired concentration in the slurry flowing into quencher tank 22. With this approach, a wide range of solids content is attainable from the absorber discharge stream.
Because plant operating conditions, i.e., load factor and S02 gas content, are constantly varying, the rate ~r, r , llZ9181 of solids generation in the absorber circuit, and the amount of water required to enter the quencher circuit are also changing. To allow the absorber system to react to the process requirements for water versus solids in the slurry a process signal is utilized. This siqnal relates the S02 mass flow into the absorber tower, absorber slurry density, or any other process variable which changes with changing S02 mass flow to the absorber tower to the required concentration of slurry discharge from the absorber loop to the quencher tank. The signal is fed to a controller (not show) which maintains the concentration of solids discharge to the quencher tank at the desired level.
i;
~,
Claims (19)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of operating a two-loop gas stream quencher-scrubber for scrubbing sulfur dioxide from a gas stream comprising the steps:
(a) quenching in a first loop the gas stream with a first water slurry containing alkali solids;
(b) directing the discharge from the quencher to a quencher liquid storage tank;
(c) scrubbing in a second loop the quenched gas stream with a second water slurry, isolated from the first water slurry, and containing alkali solids in a sulfur dioxide absorber;
(d) controlling recycled water and selective utilization of high and low solids streams from a separator by:
1. separating the water slurry discharges from the sulfur dioxide absorber into a low solids overflow stream and a high solids under-flow stream in a liquid-solids concentrator;
2. directing the high solids portion of the scrubbing slurry to the quencher liquid storage tank;
3. continuously dewatering a portion of the quencher slurry from the quencher liquid storage tank; and 4. disposing of the solids from the dewatering step while returning the water to the quencher liquid storage tank.
2. directing the high solids portion of the scrubbing slurry to the quencher liquid storage tank;
3. continuously dewatering a portion of the quencher slurry from the quencher liquid storage tank; and 4. disposing of the solids from the dewatering step while returning the water to the quencher liquid storage tank.
2. The method defined in claim 1 wherein the scrubbed gas stream is passed through a demister; the demister is washed with water and the wash water from the demister is added to the discharge liquid from the scrubber in the second loop.
3. The method defined in claim 2 including directing the low solids overflow stream from step (d) to a scrubbing liquid holding tank; and as needed, adding water and an alkali reagent to said holding tank.
4. The method defined in claim 3 wherein the alkali reagent is lime or limestone.
5. The method defined in claim 1 wherein the solids content of the water slurry in the sulfur dioxide absorber is maintained between about 6% to 14% solid content.
6. The method defined in claim 1 wherein the high solids stream from the separation step has a solids content in the range of 10% to 50% and the low solids stream has a solids content in the range of 3% to 10%.
7. The method defined in claim 1 wherein the alkali solids comprise CaCO3 and the solids disposed of in step (4) are primarily calcium sulfate.
8. The method defined in claim 4 wherein the high solids stream from step (d) is primarily water and calcium carbonate.
9. The method defined in claim 4 wherein the high solids underflow stream is primarily water, calcium sulfite and calcium sulfate.
10. A method of operating a two-loop gas stream quench-scrubber for scrubbing sulfur dioxide from a gas stream comprising the steps of:
(a) quenching in a first loop the gas stream with a first water slurry containing alkali solids;
(b) scrubbing in a second loop the quenched gas stream with a second water slurry, isolated from the first water slurry, and containing alkali solids;
(c) maintaining the alkali solids content in the scrubbing slurry at a level between 6% to 15% relative to the sulfur dioxide content in the gas stream by adding alkali solids and water as required;
(d) maintaining the alkali solids content in the quenching slurry at a level greater than 3% relative to the sulfur dioxide content in the gas stream by selectively withdrawing from the scrubbing slurry portions having higher or lower alkali solids content than said level, thereby raising or lowering the alkali solids content in the quenching slurry.
(a) quenching in a first loop the gas stream with a first water slurry containing alkali solids;
(b) scrubbing in a second loop the quenched gas stream with a second water slurry, isolated from the first water slurry, and containing alkali solids;
(c) maintaining the alkali solids content in the scrubbing slurry at a level between 6% to 15% relative to the sulfur dioxide content in the gas stream by adding alkali solids and water as required;
(d) maintaining the alkali solids content in the quenching slurry at a level greater than 3% relative to the sulfur dioxide content in the gas stream by selectively withdrawing from the scrubbing slurry portions having higher or lower alkali solids content than said level, thereby raising or lowering the alkali solids content in the quenching slurry.
11. The method as defined in claim 10 wherein the alkali solids comprise CaCO3 and fresh water and concentrated slurry of the alkali solids are introduced into the scrubbing slurry and cycled slurry is withdrawn from the scrubbing slurry and introduced into the quenching slurry to avoid buildup of dissolved calcium sulfate compounds in the scrubbing slurry and to provide a sub-stantially open first loop.
12. The method as defined in claim 11 wherein a portion of said first slurry is withdrawn and water is extracted from said withdrawn slurry and returned to said first slurry.
13. The method as defined in claim 11 wherein slurry is continuously fed from the scrubbing slurry to the quenching slurry to partially substitute for the slurry lost in the quenching process.
14. The method as defined in claim 13 wherein a portion of the quenching slurry is withdrawn and dewatered and the water is returned to the quenching slurry while the solids are discarded.
15. The method as defined in claim 14 wherein the quenching slurry and the scrubbing slurry are circulated in separate scrubbing loop and quencher loop systems.
16. The method as defined in claim 11 wherein the quantity of water added to both the scrubbing loop and the quencher loop is controlled by selectively withdrawing slurry portions from the scrubbing slurry loop having a higher alkali solids content and returning slurry portions to the scrubbing slurry loop having a lower alkali solids content thereby reducing the amount of water required to be added to the scrubbing loop to maintain the solids content at a desired level, and increasing the amount of water added to the scrubbing loop by withdrawing slurry portions having lower alkali solids content and returning slurry portions having higher alkali solids content.
17. The method as defined in claim 16 wherein the scrubbing of the gas stream occurs in a closed vessel in which the gas enters from the bottom and exits from the top and the quenching slurry is sprayed into the gas stream near the bottom of the vessel and the absorber slurry is sprayed into the gas stream near the bottom of the vessel and the absorber slurry is sprayed into the gas stream near the top of the vessel and each sprayed slurry is collected separately.
18. The method as defined in claim 17 wherein water is sprayed into the gas stream in the vessel above the scrubbing spray and the sprayed water is collected with the scrubbing slurry.
19. A method of operating a two-loop gas stream quencher-scrubber for scrubbing sulfur dioxide from a gas stream comprising the steps:
(a) passing the gas stream through a vessel from the bottom and out the top in which are located lower level quencher sprays, middle level scrubbing sprays and upper level demister sprays;
(b) quenching the gas stream with a first water slurry containing CaCO3 solids and collecting the quenching slurry in a first separate loop system;
(c) scrubbing the quenched gas stream with a second water slurry containing CaCO3 solids and collecting the scrubbing slurry in a second separate loop system isolated from the first loop system;
(d) spraying fresh water into the gas stream adjacent the top of the vessel and collecting the water with the quenching slurry;
(e) maintaining the CaCO3 solids content in the scrubbing slurry at a level between 3% and 10% relative to the sulfur dioxide content in the gas stream by adding concentrated slurry of CaCO3 solids as required;
(f) continuously withdrawing a portion of the circulated absorber slurry to avoid buildup of dissolved calcium sulfate compounds in the second loop system and introducing such withdrawn portion into the first slurry loop;
(g) withdrawing a portion of the quencher slurry, removing the solids from such withdrawn portion and returning the remaining water to the first slurry loop thereby defining a substantially closed loop system; and (h) maintaining the CaCO3 solids content in the quencher slurry at a level greater than 3% relative to the sulfur dioxide content in the gas stream by selectively withdrawing scrubbing slurry portions having higher or lower CaCO3 solids content from the second loop system thereby raising or lowering the CaCO3 solids content in the quenching slurry.
(a) passing the gas stream through a vessel from the bottom and out the top in which are located lower level quencher sprays, middle level scrubbing sprays and upper level demister sprays;
(b) quenching the gas stream with a first water slurry containing CaCO3 solids and collecting the quenching slurry in a first separate loop system;
(c) scrubbing the quenched gas stream with a second water slurry containing CaCO3 solids and collecting the scrubbing slurry in a second separate loop system isolated from the first loop system;
(d) spraying fresh water into the gas stream adjacent the top of the vessel and collecting the water with the quenching slurry;
(e) maintaining the CaCO3 solids content in the scrubbing slurry at a level between 3% and 10% relative to the sulfur dioxide content in the gas stream by adding concentrated slurry of CaCO3 solids as required;
(f) continuously withdrawing a portion of the circulated absorber slurry to avoid buildup of dissolved calcium sulfate compounds in the second loop system and introducing such withdrawn portion into the first slurry loop;
(g) withdrawing a portion of the quencher slurry, removing the solids from such withdrawn portion and returning the remaining water to the first slurry loop thereby defining a substantially closed loop system; and (h) maintaining the CaCO3 solids content in the quencher slurry at a level greater than 3% relative to the sulfur dioxide content in the gas stream by selectively withdrawing scrubbing slurry portions having higher or lower CaCO3 solids content from the second loop system thereby raising or lowering the CaCO3 solids content in the quenching slurry.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US2557779A | 1979-03-30 | 1979-03-30 | |
| US025,577 | 1979-03-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129181A true CA1129181A (en) | 1982-08-10 |
Family
ID=21826867
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA347,516A Expired CA1129181A (en) | 1979-03-30 | 1980-03-12 | So.sub.2 scrubbing system for flue gas desulfurization |
Country Status (14)
| Country | Link |
|---|---|
| JP (1) | JPS6057364B2 (en) |
| AT (1) | AT379322B (en) |
| AU (1) | AU532453B2 (en) |
| BE (1) | BE882464A (en) |
| CA (1) | CA1129181A (en) |
| CH (1) | CH638404A5 (en) |
| DE (1) | DE3011592A1 (en) |
| DK (1) | DK152177C (en) |
| ES (1) | ES8102833A1 (en) |
| FR (1) | FR2452466A1 (en) |
| GB (1) | GB2050325B (en) |
| IT (1) | IT1193525B (en) |
| SE (1) | SE450553B (en) |
| ZA (1) | ZA801607B (en) |
Families Citing this family (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3240317C2 (en) * | 1982-10-30 | 1986-06-12 | Gottfried Bischoff Bau kompl. Gasreinigungs- und Wasserrückkühlanlagen GmbH & Co KG, 4300 Essen | Process for the production of calcium sulphate dihydrate in the course of the desulphurisation of flue gases from power plant boiler systems |
| DE3433707A1 (en) * | 1983-06-18 | 1986-04-03 | Hölter, Heinz, Dipl.-Ing., 4390 Gladbeck | Apparatus for introducing scrubbed flue gases into a cooling tower |
| JPS6058230A (en) * | 1983-09-09 | 1985-04-04 | Babcock Hitachi Kk | Waste gas desulfurization and apparatus thereof |
| JPS60172335A (en) * | 1984-02-20 | 1985-09-05 | Babcock Hitachi Kk | Wet type stack gas desulfurization apparatus |
| DE3435472A1 (en) * | 1984-09-27 | 1986-03-27 | Hölter, Heinz, Dipl.-Ing., 4390 Gladbeck | Water flushing for demister packages downstream of flue gas desulphurisation plants |
| DE3437965A1 (en) * | 1984-10-17 | 1986-04-24 | Knauf-Research-Cottrell GmbH & Co Umwelttechnik KG, 8715 Iphofen | METHOD AND DEVICE FOR SEPARATING SO (DOWN ARROW) 3 (DOWN ARROW), SULFURIC ACID AND SULFURIC ACID LEAVES FROM SMOKE GASES |
| DE3632896A1 (en) * | 1986-09-27 | 1988-04-07 | Krc Umwelttechnik Gmbh | METHOD FOR WET REMOVING SULFUR DIOXIDE |
| DE3721684A1 (en) * | 1987-07-01 | 1989-01-12 | Krc Umwelttechnik Gmbh | METHOD FOR WET REMOVING SULFUR DIOXIDE |
| CA2030480A1 (en) * | 1989-12-12 | 1991-06-13 | William Downs | Chloride controls in fossil fuel fired wet scrubbing process |
| DE4345364C2 (en) * | 1993-09-15 | 1997-10-02 | Steinmueller Gmbh L & C | Gas scrubbing esp. desulphurisation process |
| DE4338379C2 (en) * | 1993-11-10 | 1999-02-18 | Steinmueller Gmbh L & C | Process for removing sulfur dioxide from a gas stream |
| US5451250A (en) * | 1994-05-11 | 1995-09-19 | The Babcock & Wilcox Company | Method of convert a double-loop flue gas desulfurization system to a single-loop system |
| DE19730228A1 (en) * | 1997-07-15 | 1999-01-21 | Abb Patent Gmbh | Removing pollutant gas from combustion plant exhaust gas |
| DE10346519A1 (en) * | 2003-10-02 | 2005-05-04 | Uhde Gmbh | Process for the removal of ammonia and dust from an exhaust gas resulting from the production of fertilizers |
| WO2007075485A2 (en) | 2005-12-19 | 2007-07-05 | Fluor Technologies Corporation | Two-stage quench scrubber |
| EP1912723A4 (en) * | 2006-05-03 | 2011-08-03 | Snc Lavalin Europ N V Sa | Gas quench and scrubber draw-off system |
| EA201000896A1 (en) | 2007-12-28 | 2011-06-30 | Калера Корпорейшн | CO BINDING METHODS |
| US20100239467A1 (en) | 2008-06-17 | 2010-09-23 | Brent Constantz | Methods and systems for utilizing waste sources of metal oxides |
| CA2700768C (en) | 2008-07-16 | 2014-09-09 | Calera Corporation | Co2 utilization in electrochemical systems |
| US7993500B2 (en) | 2008-07-16 | 2011-08-09 | Calera Corporation | Gas diffusion anode and CO2 cathode electrolyte system |
| CA2700770C (en) | 2008-09-30 | 2013-09-03 | Calera Corporation | Co2-sequestering formed building materials |
| US8869477B2 (en) | 2008-09-30 | 2014-10-28 | Calera Corporation | Formed building materials |
| US7815880B2 (en) | 2008-09-30 | 2010-10-19 | Calera Corporation | Reduced-carbon footprint concrete compositions |
| US9133581B2 (en) | 2008-10-31 | 2015-09-15 | Calera Corporation | Non-cementitious compositions comprising vaterite and methods thereof |
| WO2010093716A1 (en) | 2009-02-10 | 2010-08-19 | Calera Corporation | Low-voltage alkaline production using hydrogen and electrocatlytic electrodes |
| JP2012519076A (en) | 2009-03-02 | 2012-08-23 | カレラ コーポレイション | Gas flow complex contaminant control system and method |
| US20110247336A9 (en) | 2009-03-10 | 2011-10-13 | Kasra Farsad | Systems and Methods for Processing CO2 |
| US20140072483A1 (en) * | 2012-09-10 | 2014-03-13 | Mitsubishi Heavy Industries, Ltd. | Desulfurization device and particulate collection system |
| CN104984655A (en) * | 2015-06-05 | 2015-10-21 | 中电投远达环保工程有限公司 | Slurry gathering device assembly used in wet desulfurization tower |
| EP3135364B1 (en) | 2015-08-31 | 2021-04-21 | Steinmüller Engineering GmbH | Method for exhaust gas desulfurization |
| CN105251336B (en) * | 2015-10-21 | 2017-12-01 | 中冶华天工程技术有限公司 | Sodalime double alkali method double circulation desulphurization technique and system |
| CN106039755B (en) * | 2016-07-22 | 2018-03-02 | 京能（锡林郭勒）发电有限公司 | A kind of flue gas condensing water pumping system |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3396514A (en) * | 1966-11-07 | 1968-08-13 | Babcock & Wilcox Co | Gas cleaning system |
| US3632306A (en) * | 1969-02-18 | 1972-01-04 | Chemical Construction Corp | Removal of sulfur dioxide from waste gases |
| JPS5112026B2 (en) * | 1971-11-30 | 1976-04-15 | ||
| GB1410037A (en) * | 1972-10-04 | 1975-10-15 | Mitsubishi Heavy Ind Ltd | Desulphurizing of gases |
| DE2249874C3 (en) * | 1972-10-11 | 1979-01-18 | Mitsubishi Jukogyo K.K., Tokio | Process for removing sulfur dioxide from combustion exhaust gases |
| US3907523A (en) * | 1972-12-26 | 1975-09-23 | Krebs Engineers | Method for removing SO{HD 2 {B from gases |
| US3995006A (en) * | 1973-04-05 | 1976-11-30 | The Babcock & Wilcox Company | Sulphur dioxide absorption system |
| GB1529804A (en) * | 1974-12-11 | 1978-10-25 | Exxon Research Engineering Co | Purification of pollutant-containing gases |
| BE853325A (en) * | 1975-10-09 | 1977-10-07 | Pfizer | METHOD AND APPARATUS FOR REDUCING THE SULPHUROUS ANHYDRIDE CONTENT OF A HOT FLUE GAS |
| US4198380A (en) * | 1975-11-24 | 1980-04-15 | Rockwell International Corporation | Absorption of sulfur oxides from hot gases |
| DE2735566A1 (en) * | 1977-08-06 | 1979-02-22 | Metallgesellschaft Ag | METHOD FOR REMOVING FLUOROUS COMPOUNDS AND SULFUR DIOXIDE FROM EXHAUST GASES |
-
1980
- 1980-03-12 CA CA347,516A patent/CA1129181A/en not_active Expired
- 1980-03-13 GB GB8008551A patent/GB2050325B/en not_active Expired
- 1980-03-19 ZA ZA00801607A patent/ZA801607B/en unknown
- 1980-03-19 AU AU56573/80A patent/AU532453B2/en not_active Ceased
- 1980-03-24 ES ES489860A patent/ES8102833A1/en not_active Expired
- 1980-03-25 SE SE8002289A patent/SE450553B/en not_active IP Right Cessation
- 1980-03-26 DE DE3011592A patent/DE3011592A1/en active Granted
- 1980-03-26 AT AT0162880A patent/AT379322B/en not_active IP Right Cessation
- 1980-03-27 BE BE0/199974A patent/BE882464A/en not_active IP Right Cessation
- 1980-03-27 DK DK132480A patent/DK152177C/en not_active IP Right Cessation
- 1980-03-27 JP JP55039606A patent/JPS6057364B2/en not_active Expired
- 1980-03-27 CH CH240180A patent/CH638404A5/en not_active IP Right Cessation
- 1980-03-28 FR FR8007038A patent/FR2452466A1/en active Granted
- 1980-03-28 IT IT21045/80A patent/IT1193525B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| CH638404A5 (en) | 1983-09-30 |
| DE3011592C2 (en) | 1988-11-17 |
| AT379322B (en) | 1985-12-27 |
| ZA801607B (en) | 1981-07-29 |
| DK152177B (en) | 1988-02-08 |
| DK152177C (en) | 1988-07-11 |
| ES489860A0 (en) | 1981-02-16 |
| JPS55142529A (en) | 1980-11-07 |
| ATA162880A (en) | 1985-05-15 |
| SE8002289L (en) | 1980-10-01 |
| IT1193525B (en) | 1988-07-08 |
| IT8021045A0 (en) | 1980-03-28 |
| JPS6057364B2 (en) | 1985-12-14 |
| ES8102833A1 (en) | 1981-02-16 |
| AU5657380A (en) | 1980-10-02 |
| BE882464A (en) | 1980-07-16 |
| DK132480A (en) | 1980-10-01 |
| AU532453B2 (en) | 1983-09-29 |
| FR2452466A1 (en) | 1980-10-24 |
| GB2050325A (en) | 1981-01-07 |
| SE450553B (en) | 1987-07-06 |
| DE3011592A1 (en) | 1980-10-30 |
| GB2050325B (en) | 1983-02-16 |
| FR2452466B1 (en) | 1983-04-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1129181A (en) | So.sub.2 scrubbing system for flue gas desulfurization | |
| US3944401A (en) | Process for the removal of gaseous impurities from the exhaust gases of a contact-process plant for the production of sulfuric acid | |
| US4690807A (en) | Process for the simultaneous absorption of sulfur oxides and production of ammonium sulfate | |
| US6214097B1 (en) | Flue gas scrubbing apparatus | |
| US4431617A (en) | Methods for removing malodorous sulfur compounds from pulp mill flue gases and the like by using green liquor | |
| US4696804A (en) | Method for treating SO2, SO3 and dust simultaneously | |
| US5635149A (en) | Wet scrubbing method and apparatus for removing sulfur oxides from combustion effluents | |
| CN1036444C (en) | FGD performance enhancement by hydroclone | |
| US2142406A (en) | Apparatus for the wet purification of gases | |
| US4322392A (en) | SO2 Scrubbing system for flue gas desulfurization | |
| US4250152A (en) | Sulfur dioxide scrubber with hyroclone separator | |
| RU2149679C1 (en) | Method of scrubbing and device for removal of sulfur oxides from combustion products | |
| US4351804A (en) | Sulfur dioxide scrubber with hydroclone separator | |
| US5310528A (en) | Method for purification of waste gases | |
| CA1105371A (en) | Flue gas scrubbing additive utilization | |
| EP0637988A1 (en) | Method for purification of waste gases | |
| US4618482A (en) | Method for controlling a concentration of slurry in wet flue gas desulfurization apparatus | |
| US4590048A (en) | Removal of sulfur oxides from gas streams with ammonium sulfite | |
| JPS59230620A (en) | Slurry concentration control method of wet waste gas desulfurization apparatus | |
| JPS6099329A (en) | Stack gas desulfurization apparatus by wet process | |
| GB2163417A (en) | Controlling slurry concentration in wet flue gas desulphurization apparatus | |
| CA1250410A (en) | Removal of sulfur oxides from gas streams with ammonium sulfite | |
| WO1993003824A1 (en) | Method for purification of waste gases | |
| Risse et al. | The bischoff flue gas desulfurization process in the power plants of borssele and maasvlakte in the Netherlands | |
| MXPA96006215A (en) | Improved method of wet deposition and apparatus to remove sulfur oxides from combust effluents |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |