DE2510241A1 - PROCESS FOR THE ABSORPTION OF GASEOUS COMPONENTS FROM GASES - Google Patents

Description

METALLGESELLSCHAFT Frankfurt / M., February 5, 1975

Aktiengesellschaft f.chr / lIGa

6000 Frankfurt / M. ^;

and

BAYER AG prov. No. 7614 LC

5090 Leverkusen

Process for the absorption of gaseous components from gases

The invention relates to a method for the absorption of gaseous Components from gases by means of absorption liquids, in particular for the absorption of SO ^ or moisture by means of sulfuric acid and / or for the absorption of water from dilute sulfuric acid in hot gases, whereby in cocurrent to the gases in the upper part of a vertical Venturi absorber is injected absorption liquid, - a large part of the injected absorption liquid into a sump below the outlet end of the vertical Venturi absorber is deposited, the gases with the remaining absorption liquid below the outlet end of the vertical Venturi absorber and above the sump into an approximately horizontally arranged Venturi absorber, the mixture of gases and absorption liquid from the horizontal Venturi absorber into a settling room with a Scraper layer for separating fine droplets in the upper part of the settling space is passed in front of the gas outlet, and the absorption liquid into a sump at the bottom of the settling room is deposited.

In the absorption of gaseous components from gases by means of absorption liquids, with no solid products should arise, but the gaseous components experience a solution in the absorption liquid through absorption, the effort required for the absorber and the absorption should be kept as low as possible and yet the required absorption capacity or the required degree of absorption can be achieved. The same requirements apply accordingly for the absorption of water from dilute sulfuric acids in hot gases, whereby the acids are concentrated and impurities contained in the acids should not affect the process ".. ■ ■

609839/0416 " ² ~.

An intermediate absorber for the absorption of SO _{7 is} known, in which the gases are treated in a vertical Venturi absorber with sulfuric acid in cocurrent, the major part of the injected acid is deposited in a sump below the outlet end of the Venturi absorber, the gas with the rest Acid is passed into a horizontal Venturi absorber and post-treated there, the horizontal Venturi absorber being arranged below the outlet end of the vertical Venturi absorber and above the sump, the mixture of gas and remaining absorption acid from the horizontal Venturi absorber being passed into a settling room with a stripping layer in the upper part , the remaining absorption acid deposited in a sump at the bottom of the settling space, and the gas, largely freed from SO, is discharged from the settling space (DT-PS 2 050 579).

There is also a method for absorbing gaseous constituents known from gases, in which most of the absorption of the gaseous components in a vertical Venturi absorber takes place through absorption liquid injected in cocurrent, a large part of absorption liquid is deposited in a sump below the outlet end of the vertical Venturi absorber, the gases with the rest Absorbent liquid below the outlet end of the vertical Venturi absorber and above the sump into an approximately horizontally arranged Venturi absorber are injected into the horizontal Venturi absorber in direct current with the gases absorption liquid, the mixture of gases and absorption liquid is passed from the horizontal venturi absorber into a settling room, there passed through a packing layer and the packing layer is sprayed with absorption liquid from above in countercurrent to the direction of flow of the gases, the gases be discharged through a stripper layer in the upper part of the settling space and then out of the settling space, and

- 3 -

609839/0416

the absorption liquid is deposited in a sump at the bottom of the settling space (DT-OS 2 050 580).

These processes produce desired or very high degrees of absorption with small absorber dimensions, low operating costs and high throughput rates.

It is known to remove SO ^ and / or sulfuric acid mist injecting dilute sulfuric acid from the dry end gases of sulfuric acid contact systems into the end gases, enrich the gases according to the water vapor partial pressure of the dilute sulfuric acid, which in the End gases formed from SO ^ and the existing sulfuric acid to be deposited and the remaining water vapor-containing gas carried away as exhaust gas, with diluted waste acid in the Direct current to the end gases is injected into a vertical venturi, most of the acid injected into one Separated sump under the Venturi, the gas with the remaining acid is diverted and into a post-separation room a packing layer, where the remaining acid is deposited and the moist gas is discharged (DT-OS 2 145 546).

This process enables an economical and technically simple concentration of thin sulfuric acids.

It is also known for the deposition of very fine grains Solids from gases to treat the gases in a vertical venturi scrubber with liquid aerosols, the Liquid aerosols must be the same size as the solids, and the gases from the very high velocity injected liquid aerosols are fed into the venturi scrubber, from the lower part of the venturi scrubber in the Again liquid aerosols are injected in countercurrent and the solids coagulated in this way are separated in a cyclone and the gases exiting the cyclone are washed in a packed tower, the

- 4 -B 0 9 8 3 9 / Π Α 1 6

Packing tower also in the same and. Countercurrent with liquid aerosols is sprayed. Instead of the packing tower, electrostatic deposition or a deposition by means of sound waves take place (US Pat. No. 2,935,375).

This process is suitable for the separation of very fine-grained solids, but not for absorption of gaseous components or the concentration of thin sulfuric acids. So must also Separation of SO ^ from gases in addition to solids a washing liquid be used with potassium carbonate, which creates solids.

Furthermore, a device for the deposition of SOp and Dust from flue gases is known, several nozzles being arranged one above the other in a washing tower in the washing tower axis which inject scrubbing water both in cocurrent and in countercurrent to the direction of flow of the gas, the raw gas inlet nozzle with its end forms a collar in the washing tower, this collar of additional nozzles is surrounded by washing water for injection, and lime or a lime-water suspension in the raw gas before it enters the washing tower is injected (DT-PS 2 150 835).

In this device, too, solids must be introduced to separate the gaseous constituents, as a result of which in turn, solids accumulate as a washing product. There is also a large number of nozzles - some of them ring-shaped distributed over the scope - necessary what to a relatively high costs.

The invention is based on the object, the known method of absorption of gaseous components without Accumulation or use of solids or the concentration of thin sulfuric acids by means of hot gases in in such a way that the efficiency is improved under the same conditions or under the same conditions

R Π 9 8 3 9 / fi U 1 6

Efficiency, the investment costs and operating costs can be reduced.

This object is achieved according to the invention in that in the outlet end of the vertical and / or horizontal Venturi liquid is injected in countercurrent to the direction of flow of the gases.

When absorbing SO, or moisture it becomes concentrated Sulfuric acid or oleum is injected as an absorption liquid. When concentrating dilute sulfuric acid this dilute sulfuric acid is injected and dry gases or gases with a low moisture content initiated to absorb water from the dilute sulfuric acid. End gases are preferred as dry gases used by sulfuric acid contact systems, from which at the same time still remaining sulfuric acid mist during the concentration and SO ^ can be removed. It can, however hot flue gases or air with a low moisture content can also be used.

Through the additional injection of liquid in countercurrent the mixture of gas and liquid formed when injecting in cocurrent becomes the direction of flow of the gases on the one hand again swirled and mixed and on the other hand fresh liquid droplets for another Response offered. Whether a single or double injection takes place in countercurrent depends on the desired Degree of absorption or concentration.

A preferred embodiment is that in the The inlet end of the horizontal Venturi liquid is injected in cocurrent to the direction of flow of the gases will. This results in a further increase in the degree of absorption or concentration.

B09839 / 0416

A preferred embodiment is that most of the remaining liquid from the in the horizontal Venturi entering mixture of gases and liquid in the inlet part of the horizontal venturi through internals separated and directed into the sump under the vertical venturi. Through fixtures that act as impact devices act in which. A large part of the entry part of the horizontal venturi absorber does not enter the sump Separated absorption liquid under the vertical Venturi absorber in the inlet part and flows back into the sump under the vertical venturi absorber. The fixtures in the entry part can be used as pockets be formed into which the absorption liquid flows and which are connected to the sump via lines. Through this the circuits of the absorption liquid of the vertical Venturi absorber and of the settling space can be as great as possible are kept separate and / or operated with absorption liquids of very different concentrations will. Furthermore, the absorption effect or concentration is improved in the subsequent treatment.

A preferred embodiment is that the gases in the settling space in front of the stripper layer by a Packing layer are passed and the packing layer is acted upon with absorption liquid from above in countercurrent to the direction of flow of the gases. This becomes a very high degree of absorption and a safety reserve achieved if fluctuations in the gas composition occur or a nozzle fails. The height of the packing layer is 0.5 to 2 m. The packing layer can with Absorber liquid are sprinkled or sprayed.

A preferred embodiment consists in that about 5 to 50 %, preferably 10 to 35 %, of the total liquid is injected into the venturi (s) in countercurrent to the direction of flow of the gases. With this ratio, a good degree of absorption or a good concentration is achieved.

609 8 39/0416

Another preferred embodiment is that about 10 to 75 %, preferably 40 to 70 %, of the total liquid is injected into the venturi (s) in cocurrent to the direction of flow of the gases. This ratio also results in a good degree of absorption or good concentration achieved.

The invention is explained in more detail with reference to the figures, the figures showing the following applications:

Fig. 1: Air drying with concentrated sulfuric acid Fig. 2: partial absorption of SO-z with oleum

Fig. 3: partial absorption of SO ^ with concentrated sulfuric acid

Fig. 4: extensive absorption of SO, with concentrated sulfuric acid

Fig. 5: Almost complete absorption of SO ^ with concentrated sulfuric acid

Fig. 6: Drying of gases containing SO2 in the first Stage with dilute and in the second stage with concentrated sulfuric acid

Fig. 7: Almost complete absorption of SO ₇ , with oleum in the first stage and with concentrated sulfuric acid in the second stage.

Embodiment 1 (Fig. 1)

Via line 1 80% saturated with water vapor 10,000 NNR / h atmospheric air with a temperature of 10 ° C, ie with 8 000 mg H _o 0 / Nm in the venturi from he sorb 2 initiated. In the venturi 3, the air is brought into contact with 15 m / h sulfuric acid with 96% by weight, which is introduced via line 9a and atomized with the nozzle 9. 5 m / h of sulfuric acid at 96% by weight are introduced via line 10a and atomized in countercurrent with the countercurrent nozzle 10 in space 4.

B Π 9 8 3 U / 0 A 1 6

The predried air-acid mixture is vortexed in the second Venturi 5, and flows through the tower 7, the drop separator 6 and line 8. The degree of drying is 98.5%, so that the air mg to about 120 H ^ O / n NR ⁵ was dried . The acid collects in the sumps 2a and 7a and is conveyed via the lines 11, 12 and 13 to the pump 14 and pressed again via the line 15 to the nozzles 9 and 10 via the lines 9a and 10a. "About 2 nr / h of strengthening acid with 98.5 wt. About 2117 hours of drying acid are returned to the absorber circuit via line 17.

Embodiment 2 (Fig. 2)

10 000 Nm ³ / h SO, -containing gas with 8.0 vol. 96 SO, ie with approx. 290 000 mg SO, / Nm ³ at a temperature of 150 ⁰ C are introduced into the Venturi absorber 2 via line 1. In the venturi 3, the gas is brought into contact with 38 m / h oleum with 25 % ^{free SO 2} and a temperature of 50 ° C., which is introduced via line 9 a and atomized with the nozzle 9. In the venturi 3 and in the second venturi 5, the gas is cooled and pre-absorbed. 35 nr / h oleum with 25 % ^{free SO 2} and a temperature of 50 ° C. are atomized with the countercurrent nozzle 18 via line 18a. After flowing through the droplet separator 6, the absorbed gas leaves the tower 7 via line 8. The degree of absorption is approx. 80 %, so that the gas still approx. 58,000 mg SO, that is approx. 1.6% by volume SO - ^, contains. The acid collects in the sumps 2a and 7a and is conveyed via the lines 11 and 12, the acid cooler 13a, the line 13 to the pump 14 and pressed via the line 15 again via the lines 9a and 18a to the nozzles 9 and 18. 3.2 nr / h sulfuric acid with 98.5% by weight are added via line 16 from the monohydrate absorber circuit into the oleum absorber circuit. Production is released via line 17.

- 9 609839/0416

_ Q -

Embodiment 3 (Fig. 3)

Via line 1 to 10,000 NnrVh SO ^ -containing gas with 9.8 VoI.96 SO ^, that is initiated with about 350 000 mg SO ^ / n NR ⁵ and a temperature of 220 ⁰ C in the venturi absorber. 2 In the venturi 3, the gas is 55 m with / h sulfuric acid with 98.3 wt. #, And brought to a temperature of 8O ⁰ C, which is introduced via line 9a and injected with the nozzle 9 in contact. Via line 10a 15 m / h of sulfuric acid are introduced at 98.3 Gew.96 and a temperature of 8O ⁰ C and atomized with the Gegenstromdüse 10 in the space 4 in counterflow. 98% of the SO ^ is absorbed in venturi 3 and space 4. The gas is then passed into the second venturi 5. Via line 18a 25 nr / h sulfuric acid with 98.3 wt.% At a temperature of 8O ⁰ C with 18 Gegenstromdüse be atomized. The absorbed gas exits after passing through the demister 6 the tower 7 via conduit 8. The total absorption coefficient is 99% _f so that the gas 3 500 mg SO ^ / NNR contains. The acid collects in the sumps 2a and 7a and is conveyed via lines 11 and 12, the acid cooler 13a, the line 13 to the pump 14 and via line 15 again via the lines 9a, 10a and 18a to the nozzles 9, 10 and 18 pressed. About 26 m / h of sulfuric acid at 96% by weight are added via line 16 from the dryer circuit into the absorber circuit. The production is discharged via line 17 and cooled to approx. 45 ° C. in cooler 17a.

Embodiment 4 (Fig. 4)

10 000 Nm ³ / h 30, -containing gas with 9.8% by volume SO ₃ , ie with approx. 350 000 mg SO ^ / Nm ^ and a temperature of 220 ° C., are introduced into the Venturi absorber 2 via line 1 . In the venturi 3, the gas is 55 m with / h sulfuric acid with 98.3 Gew.?6 and a temperature of 8O ⁰ C, which is introduced via line 9a and injected with the nozzle 9, brought into contact. Via line 10a will be 10 1117h sulfuric acid with 98.3 Gew.9S and a temperature of 8O ⁰ C

- 10 B09839 / 0416

initiated and atomized with the countercurrent nozzle 10 in space 4 in countercurrent. 98% of the SCU is absorbed in venturi 3 and space 4. The gas is then passed into the second venturi 5. 25 m / h sulfuric acid at 98.3 % by volume and a temperature of 80 ° C. are injected into the venturi 5 via line 19a and nozzle 19. 10 μr / h of sulfuric acid with 98.3% by weight and a temperature of 80 ° C. are atomized with the countercurrent nozzle 18 via line 18a. After flowing through the droplet separator 6, the absorbed gas leaves the tower 7 via line 8. The total degree of absorption is 99.8 %, so that the gas still contains 700 mg SO 1 / Nm. The acid collects in the sumps 2a and 7a and is conveyed via the lines 11 and 12, the acid cooler 13a, the line 13 to the pump 14 and via line 15 via the lines 9a, 10a, 18a and 19a to the nozzles 9, 10, 18 and 19 pressed. About 26 m / h of sulfuric acid at 96% by weight are added via line 16 from the dryer circuit into the absorber circuit. The production is discharged via line 17 and cooled to approx. 45 ° C. in cooler 17a.

Embodiment 5 (Fig. 5)

10 000 Nm / h SO ^ -containing gas with 1.0% by volume SO ₃ , ie with 35 600 mg SO ^ / Nm ⁵ and a temperature of 220 ° C., are introduced into the Venturi absorber 2 via line 1. In the venturi 3, the gas is brought into contact with 40 nr / h sulfuric acid at 98.8% by weight and a temperature of 60 ° C., which is introduced via line 9a and injected with the nozzle 9. Introduced via line 10a v / ground 10 ήγ / II sulfuric acid with 98.8 wt. % And a temperature of 60 ⁰ C and atomized with the countercurrent nozzle 10 in space 4 in countercurrent. 98.0% of the SO ^ is absorbed in venturi 3 and space 4. The gas is then passed into the second venturi 5. Through line 19a and nozzle 19 are injected with 98.8 wt,% and a temperature of 6O ⁰ C into the venturi 20 5 m ^ / hr sulfuric acid. 10 m / h of sulfuric acid with 98.8% by weight and

609839/0416 - 11 -

at a temperature of 60 ° C with the countercurrent nozzle 18 atomized. The fine rod sorption is in the sprayed packing layer 6, which is arranged in the tower 7, with 15 m / h sulfuric acid with 98.8 wt , e.g. sprinkling pipes, can be used instead of a nozzle). After flowing through the droplet separator 21, the absorbed gas leaves the tower 7 via line 8 and is passed into an exhaust gas chimney. The total degree of absorption is 99.99%, so that the gas contains only 36 mg SO ^ / Nnr. The acid collects in the sumps 2a and 7a and is conducted via the lines 11 and 12, the acid cooler 13a, the line 13 to the pump 14 and via line 15 again via the lines 9a, 10a, 18a, 19a and 20a to the nozzles 9, 10, 18, 19 and 20 pressed. About 2 nr / h sulfuric acid with 96-97% by weight from the dryer circuit are added to the absorber circuit via line 16. The production is withdrawn via line 17 and cooled to approx. 45 ° C. in cooler 17a.

Embodiment 6 (Fig. 6)

_{10 000 Nm / h SO 2} -containing gas at a temperature of 40 ° C. are 100% saturated with water vapor via line 1, ie introduced into Venturi absorber 2 with 63 100 mg EUO / Nm. In the venturi 3, the gas 45 nr / h sulfuric acid at 78 wt.% Is reacted with an acid temperature of 50 ⁰ C, which is introduced via line 9 and is introduced to the nozzle 9 into contact. 15 m / h of sulfuric acid at 78% by weight are introduced via line 10a at a temperature of 50 ° C. and atomized in countercurrent with the countercurrent nozzle 10 in space 4. About 92% of the H ₂ O is dried out in the venturi 3 and space 4, so that the gas after leaving the Venturiab sorb it s 2, ie after the first drying stage still contains about 5,000 mg of H ₂ OZNm. The predrying acid collects in the sump 2a and is over

- 12 609839 / (H16

the line 11 withdrawn. The required strengthening acid with a concentration of approx. 96% by weight sulfuric acid is added via line 16. The acid is then cooled in the cooler 13a, conveyed to the pump 14 via line 13 and pressed back to the nozzles 10 and 10 via lines 15, 9a and 10a. The production is discharged via line 17 with a concentration of 78% by weight sulfuric acid. The predried gas passes through the obliquely formed inlet part 21, into which a semi-circular baffle is installed 21a, 5 in the second venturi via line 19a and nozzle 19 are 25 m / h sulfuric acid at 96 wt.% And a temperature of 50 ⁰ C injected into the Venturi 5. Via line 18a 5 irr / h sulfuric acid at 96 wt.% And a temperature of 50 ⁰ C with 18 Gegenstromdüse atomized. After flowing through the droplet separator 6, the dried gas leaves the tower 7 via line 8 (ie the second drying stage). The degree of dryness is 99.95 % based on the inlet gas, so that the gas was _{dried to a total of 35 mg H 2} OZNm. The after-drying acid collects in the sump 7a and is passed via line 12, the acid cooler 12a to the pump 14a and pressed back to the nozzles 18 and 19 via lines 15a, 18a and 19a. The strengthening acid with a concentration of 98.5% by weight sulfuric acid is added from the SO ^ absorber circuit via line 16a. The excess drying acid with a concentration of approx. 96% by weight sulfuric acid is returned to the SO ^ absorber circuit via line 17a.

Embodiment 7 (Fig. 7)

10 000 Nm ⁵ / h SO, -containing gas with 8.0 vol.% SO ₃ , ie with approx. 290 000 mg ^{SO, / Nm 3} at a temperature of 150 ⁰ C are introduced into the Venturi absorber 2 via line 1 « In the venturi 3 the gas is brought into contact with 38 nr / h oleum with 25 % free SO- * and a temperature of 40 ° C., which is introduced via line 9a and atomized with the nozzle 9. Via line 10a, 35 m / h of oleum with 25 %

- 13 - Β09839 / Γ1416

Introduced free SO ₇ and a temperature of 40 ° C and atomized with the countercurrent nozzle 10 in space 4 in countercurrent. About 80% of the SO ^ is absorbed in the venturi 3 and space 4, so that after leaving the venturi absorber 2, ie after the first absorption stage, the gas still contains about 58,000 mg SO ^ / Nm. The oleum collects in sump 2a and is drawn off via line 11. About 3.0 nr / h sulfuric acid with 98.7% by weight from the acid circuit of the second absorption stage are added via line 16; The acid is then cooled in the cooler 13a, passed via line 13 to the pump 14 and pressed back to the nozzles 9 and 10 via lines 15 »9a and 10a. The production is released via line 17 as oleum with 25 % free SO ^. The pre-absorbed gas passes through the inclined inlet part 21, in which a semicircular baffle wall 21a is installed, into the second venturi 5. 30 m / h sulfuric acid at 98.7% by weight and a temperature of approx 100 ^° C. is injected into the venturi 5. Via line 18a 10 m / h sulfuric acid at 98.7 Gev /.^ o and a temperature of 100 ⁰ C with the Gegenstromdüse 18 are atomized. The fine rod sorption is carried out in the sprayed packing layer 6, which is arranged in the tower 7, with 15 m / h sulfuric acid at 98.7% by weight and a temperature of 80 ° C, which is introduced via line 20a and sprayed in via nozzle 20 (here one of the usual sprinkling systems, for example sprinkling pipes, can also be used instead of a nozzle). The acid is cooled beforehand in the cooler 20b. The absorbed gas leaves the second absorption stage via droplet separator 21 and line 8. The total degree of absorption, based on the inlet gas, is 99.97%, so that the gas still contains a total of about 90 mg SO ^ / Nm. The acid collects in the sump 7a and is conveyed to the pump 14a via line and printed back to the nozzles 18, 19 and 20 via lines 15a, 18a, 19a and 20a. Sulfuric acid at 96% by weight is added via line 16a from the dryer circuit to the SO- ^ absorber circuit.

609839 / OA 16 -14-

Production with 98.7% by weight of sulfuric acid is started via line 17a peeled off and cooled to approx. 45 ° C. in the cooler 17b.

The principle shown in the examples of increasing the degree of absorption of SO, or moisture in the various Working methods also apply to the absorption of other gas components or to the concentration.

The absorption of SCU can also take place with hot sulfuric acid of about 100-160 ^° C., the temperature of the gases escaping being increased accordingly and less heat being dissipated to the sulfuric acid.

The advantages of the invention are mainly that compared to the known methods in devices of the same size the degree of absorption or the concentration is increased or the devices with the same degree of efficiency can be reduced in size. This can reduce operating and investment costs. When concentrating Contaminated, dilute sulfuric acids do not cause malfunctions due to clogging despite the high degree of efficiency on.

- 15 -

Claims

609839/0 416

Claims (6)

251024 claims 1. Process for the absorption of gaseous components from gases by means of absorption liquids, in particular for the absorption of SO, or moisture by means of sulfuric acid and / or for the absorption of water from dilute sulfuric acid in hot dry "gases, with the gases in the upper part of a vertical Venturi liquid is injected, a large part of the injected liquid is deposited in a sump below the outlet end of the vertical Venturi, the gases with the remaining liquid below the outlet end of the vertical Venturi and above the sump in an approximately horizontally arranged Venturi, which Mixture of gases and liquid is passed from the horizontal venturi into a settling space with a stripping layer for separating fine droplets in the upper part of the settling space before the gas outlet, and the liquid is separated into a sump at the bottom of the settling space, marked thereby Ichnet that in the outlet end of the vertical and / or horizontal Venturi liquid in countercurrent to the direction of flow of the. Gas is injected. 2. The method according to claim 1, characterized in that liquid is injected into the inlet end of the horizontal Venturi in cocurrent to the flow direction of the gases. 3. The method according to claim 1 or 2, characterized in that the majority of the remaining liquid from the mixture of gases and liquid entering the horizontal venturi in the inlet part of the horizontal venturi is separated by internals and passed into the sump under the vertical venturi. 609839/04 16 4. The method according to claims 1 "to 3, characterized in that the gases in the settling space in front of the
Stripper layer are passed through a packing layer and the packing layer is acted upon with absorption liquid from above in countercurrent to the direction of flow of the gases. 5. The method according to claims 1 to 4, characterized in that about 5 - 50 %, preferably 10 - 35 %,
the entire liquid is injected into the venturi or venturi in countercurrent to the direction of flow of the gases. 6. The method according to claims 1 to 4, characterized in that about 10 - 75 %, preferably 40 - 70 %,
the entire liquid is injected into the venturi (s) in cocurrent to the direction of flow of the gases. 983!) / Π Α 1 6