DE1276282B - Process for the removal of hydrogen sulfide from gases containing hydrogen sulfide - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

ClOk

German class: 26 d- 8/04

Number: 1276 282

File number: P 12 76 282.2-43 (B 69479)

Filing date: November 3, 1962

Opening day: August 29, 1968

Since then there has been a need to use hydrogen sulfide containing gases, e.g. B. coke oven gas, Many processes are already used to technically process synthesis gas, natural gas, on a large scale Removal of the hydrogen sulfide from these gas mixtures and recovery of the sulfur, e.g. Am Form of sulfur dioxide became known.

In the German patent specification 159 613 there is a method for cleaning luminescent or coke oven gases described, according to which the hydrogen sulfide contained in the gases by means of a slurry of Iron hydroxide is removed in water. The hydrogen sulfide is exclusively through a chemical reaction removed from the gas. First, the trivalent iron turns into the divalent form transferred, whereby the hydrogen sulfide is oxidized to elemental sulfur. The resulting bivalent Iron reacts with additional hydrogen sulfide to form iron (II) sulfide. The slurry thus treated is then regenerated by treatment with air.

The process described in German Patent 529 698 for the desulfurization of industrial Gases consists in treating these gases with slurries of manganese dioxide in water. The resulting mixture of manganese sulfide and sulfur is then removed from the aqueous The suspension is filtered off and the remaining moist mass is oxidized by means of air. This creates Manganese (III) hydroxide and sulfur. After oxidation, the precipitate becomes drier with warmer Air dried, whereby the manganese hydroxide is decomposed into manganese dioxide and water. The dried one Manganese dioxide and sulfur-containing precipitate is then mixed with a solvent for sulfur, z. B. trichlorethylene treated, wherein the sulfur is brought into solution.

There are also known processes in which the hydrogen sulfide is catalytically in Sulfur is transferred.

So it is z. B. known, hydrogen sulfide with oxygen on activated carbon as a catalyst in a fixed bed to oxidize to sulfur, whereby the sulfur is deposited in elemental form on the coal. To Saturation of the active surface of the carbon becomes the sulfur with ammonium sulfide or another suitable solvent dissolved out. The method has the disadvantage that for cleaning larger amounts of gas, as they are often produced or used in industry, considerable amounts of activated carbon, which in turn make it necessary to set up large reaction vessels. By

Procedure for removing
Hydrogen sulfide
gases containing hydrogen sulfide

Applicant:

Badische Anilin- "& Soda-Fabrik

Aktiengesellschaft, 6700 Ludwigshafen

Named as inventor:

Dr. Günther Hamprecht,

8000 Munich-Untermenzing;

Dr. Karl Joerger, 6700 Ludwigshafen

Constant abrasion of the soft coal also gradually clogs the coal bed. This disorder can can only be eliminated by regenerating or replacing the carbon layer. Since at this time the relevant The absorber fails, which also applies to the time it takes to dissolve the sulfur, it is necessary to have a larger number of reserve reactors. Furthermore, for the Oxidation of the hydrogen sulphide required oxygen to the amount of hydrogen sulphide present in each case be coordinated, since an oxygen content is usually undesirable in the cleaned gas.

It has now been found that one can overcome these disadvantages

in the removal of hydrogen sulphide from gases by oxidation of the hydrogen sulphide to sulfur in the presence of activated charcoal can be avoided if a circulated aqueous, optionally weakly alkaline suspension of finely ground activated carbon in a first stage with the hydrogen sulfide-containing Brings gases into contact, the suspension loaded with hydrogen sulfide in a second stage, optionally at elevated temperatures, with oxygen or oxygen-containing gases treated, wherein the activated carbon is loaded with the sulfur formed, then the suspension returns to the first stage and the suspension is removed from the cycle after its effectiveness has decreased peeled off and replaced with fresh or regenerated suspension.

The process according to the invention is expediently carried out as follows: The aqueous suspension of the Finely ground activated carbon is at the top of one with

809 598/465

Filling bodies fed through, vertically standing tower step at normal or increased pressure. The hydrogen sulfide to be cleaned lead. At high hydrogen sulfide content it is containing gas mixture is expediently introduced in the lower part of the tower, the absorption in several behind and goes through the tower in countercurrent to carry out other connected towers, to the liquid stream. The with hydrogen sulfide 5 The process has the advantage that one for the Loaded activated carbon suspension runs into an over-end at the lower oxidation of the hydrogen sulfide of the tower arranged storage vessel and shot can work on oxygen, d. H. that it is not is given from here on a second trickle tower, is required, the oxygen on each one in front its lower part to turn off oxygen or oxygen-containing amount of hydrogen sulfide present. as Gases, e.g. B. air, are introduced. The oxidizing agent from this io is particularly suitable air, man Tower draining hydrogen sulfide-free suspension, but can also use pure oxygen, which, the elementary sulfur formed during oxidation to make the process more economical Contains bound to coal, gets into a moderately pumped over. One can see the oxidation of the Reservoir and will carry out from here again on the hydrogen sulfide also with oxygen, Pumped absorption tower. It may be expedient for the suspension to be developed electrolytically the suspension coming from the absorption tower is closed. After saturating the coal with sulfur, the heat and the suspension running off the oxidation tower through without interrupting operation Sulfur-containing coal suspension before entering the switchover to a second pump receiver from the absorption tower to cool, so that they can be switched between, while at the same time fresh suspen absorption and oxidation stage a temperature sion in an amount corresponding to the withdrawn amount there is a gradient. After the absorbable amount has decreased, it is added to the circuit, The ability of the activated carbon or its catalytic effectiveness in that the suspension is constantly in circulation

speed is the suspension from the circuit, z. B. after being pumped, the required catalyst can leave the oxidation level, deducted and kept extremely small by the amount. Of the fresh suspension replaced. The coal is z. B. in 25 low pressure loss allows greater gas flow rates than Centrifuges, suction filters, rotary filters or filter presses in a fixed bed and allows the use of high trickles the liquid separated and the sulfur in towers. As a result of the intensive mixing of gas known way z. B. with ammonium sulfide solution and liquid and the fine distribution of coal or another suitable solvent, the hydrogen sulfide is quickly and completely solved. After washing, the charcoal can be reabsorbed. The method according to the invention made possible will. In the case of the use of cheap light with high load on the catalytic converter, the decarbon dust For the absorption of the sulfur, the removal of the hydrogen sulfide from gases or gases results also the possibility of mixing coal and sulfur together, which only releases a small amount of hydrogen sulphide to burn to keep that easy way. To the same extent, however, it is also suitable for To obtain sulfur dioxide. 35 the purification of gases containing hydrogen sulfide in

The catalysts for the catalytic high concentration can contain. Oxidation of hydrogen sulfide known activated carbons can be used. Example 1 is particularly useful turns out to be coal dust, which is used in the production of

gas-activated coals accumulate and through a very 40 Two glass towers, each of which has a diameter of 80 mm small grain size. The coals can and their height is 1500 mm each, like by soaking with z. B. salts of copper, iron, illustrated in more detail in the figure, so with each other Cobalt and manganese have an additional activation associated with the suspension running off tower 1 Experienced. Coarse-grained coals can be applied to the usual on the head of the tower 2 and the drainage of Way, e.g. B. in Retsch, ball, pin or jet 45 tower 2 on the tower 1 can be pumped. the mills, both dry and wet on the appropriate two towers are each up to a height of Grain size are ground. The grain size of 1200 mm with Raschig rings, their diameter to be used activated carbon is expediently about 12 mm, filled. In the cycle, 8 1 from 10 to 100 μ. Suspension containing 12 g of gas-activated charcoal per liter

The suspensions contain appropriately 50 per liter of water, with an hourly throughput of 1201 about 5 to 60 g of coal. You can be pumped around by adding. The coal has a grain diameter z. B. ammonia, caustic soda, soda, sodium bicarbonate of about 30 μ. In the tower 1 are carbonate through conduit 5, potassium hydroxide solution, and potash. The like., Which introduced in the hourly 30001 of a gas mixture, which borders moved from 0.1 to 4 ° / _0, basified next 38 volume percent hydrogen, 59 volume percent will. 55 carbon dioxide and 3 volume percent carbon dioxide approximately

2 g of hydrogen sulfide and 100 mg of ammonia are suitable as fillers for the trickle towers Raschig rings and the like can, however, also contain cubic meters without filling. The body of hydrogen sulfide work, in which case the suspensions in a purified gas mixture leaves the tower through line 9. vertical pipe against the gas flow in the lower part of the tower 2, which sprays with the sulfur will. 60 hydrogen-laden suspension charged from above

In the first stage of the process, one proceeds, 100 liters of air per hour are introduced through line 6 at room temperature, since the solubility of the hydrogen sulfide leaves the tower through line 10 again in water or alkaline solvents. From the storage vessels 3 and 4, the solution can rise as the temperature falls. The oxidation suspension is withdrawn and replaced by fresh charcoal, accelerated by increasing the temperature. Q ₅ suspension. The temperature will be in. As the oxidation temperature, tower 1 is selected as kept at 15 ° C in tower 2. 7 and 8 moderate temperatures from 0 to 6O ⁰ C. The process heat exchanger are located designated for cooling or Aufläßt both in the first and in the second heating of the suspension.

With this system, 72 m ³ of the gas mentioned can be desulphurised with practically one hundred percent cleaning effect in 24 operating hours.

For example 2 _g

The tower 1 of the system described in the previous example is against a 2700 mm high Glass tube, the diameter of which is 80 mm and that up to a height of 2400 mm with a size of 15 mm Glass raschig rings is filled, replaced. The pumped suspension contains 24 g of one per liter Activated carbon, the grain diameter of which is around 30 μ, which has already been used for gas desulphurization and through Extraction of the absorbed sulfur with ammonium sulfide solution and subsequent washing out of the Ammonium sulfide has been regenerated with water. 8 l of suspension are added to the circuit at 22.degree an hourly throughput of 2001. In tower 1 there are 70001 every hour through line 5 of a gas mixture that contains 38 percent by volume of ao hydrogen, 59 percent by volume of carbon oxide and 3 percent by volume of carbon dioxide, about 2 g of hydrogen sulfide and 100 mg of ammonia per cubic meter contains, introduced. 3001 air is blown into the tower 2 every hour through line 6.

This system enables almost complete desulphurisation of 168 m ^{3 of} gas in 24 operating hours, ie 1 m ^{3 of} gas contains less than 0.5 mg of H ₂ S.

The sulfur-laden charcoal is filtered off after the suspension has been drawn off from the template 4 and used for Extract the sulfur three times with 800 ml each of an ammonium sulfide solution containing 100 g of sulfur and 220 g Contains ammonia per liter. It is then washed twice with 1.5 l of water each time to remove the to largely remove ammonium sulfide adhering to the coal. To obtain the sulfur, the Polysulphide solution evaporated, the sulfur being recovered almost quantitatively. The cleaned After being suspended in water, coal is returned to the cycle.

If an iron hydroxide suspension (cf. German Patent 159 613) of the same concentration and otherwise the same conditions as described above is used instead of the activated carbon suspension, the treated gas still contains 500 mg hydrogen sulfide per m ³ .

After an operating time of 40 hours, the cleaned gas, when using a gas with an initial content of 2.7 g / m ³ H ₂ S, even contains 611 mg / m ³ H ₂ S. This value can even be increased with increased air supply during regeneration of the iron hydroxide, which is increased from 440 l / h to 1000 l / h, cannot be improved.

Example 3

In the system described in Example 1, the tower 1 is replaced by a 2700 mm high Plexiglas tube, the diameter of which is 80 mm. The tube is filled with 20 mm Raschig rings up to a height of 2400 mm. In the circuit 101 a 3 ° / _o aqueous sodium hydroxide solution which contains per liter 6 g of a water vapor-activated charcoal with a grain size of 20 to 60 μ contains, pumped with an hourly throughput of the 1,501th

In the lower part of the tower 1 m ^{3 of} a gas are introduced every hour, the 53% CO, 30.5% H ₂ , 12% N ₂ , 3.5% CO ₂ , 0.2% O ₂ and 3.5 g Contains H ₂ S per cubic meter. The carbon dioxide contained in the gas converts the sodium hydroxide solution into sodium bicarbonate without affecting the absorption of the hydrogen sulfide.

The suspension of activated carbon loaded with hydrogen sulfide is, as described in Example 2, oxidized with air. The coal absorbs up to 300% of its own weight sulfur and is ultimately, as described in Example 2, regenerated.

The gas cleaned in this way contains less than 0.3 mg hydrogen sulfide per cubic meter.

Claims (2)

Patent claims: 1. Process for removing hydrogen sulphide from gases containing hydrogen sulphide by oxidation of the hydrogen sulfide to elemental sulfur with oxygen in the presence of activated carbon, characterized that one circulated aqueous, optionally weakly alkaline suspension of finely ground activated carbon in a first stage in contact with the gases containing hydrogen sulfide brings the suspension loaded with hydrogen sulfide in a second stage, if appropriate treated at elevated temperatures, with oxygen or oxygen-containing gases, the Activated charcoal is loaded with the sulfur formed, then the suspension is returned to the first stage returns and the suspension after its effectiveness has decreased from the cycle peeled off and replaced with fresh or regenerated suspension. 2. The method according to claim 1, characterized in that the suspension after leaving the second stage and before introduction to the first stage is cooled. Considered publications:
German patent specifications No. 159 613, 529 698. 1 sheet of drawings 809 598/465 8.68 © Bundesdruckerei Berlin