DE1244119B - Process and device for separating hydrogen sulfide and carbon disulfide from industrial exhaust air - Google Patents

Description

BOISIDES REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

B O 1 D 5 3/0 & 71 +. -

Int Cl BOId '

German class 12 e- 3/02

/ AA

Number 1244119

File number M48427IVc / 12e

Filing date 17 March 1961

Opening day 13 Juh 1967

It is known to produce carbon disulfide from exhaust air ζ B of the viscose processing industry Adsorption on activated carbon or other surface-active substances Separate substances and in the desorption of the loaded adsorbent by means of steam from the recover condensed desorbate

It is also known to produce hydrogen sulfide from technical oxygen-free gas mixtures, in particular coke oven gas, on activated carbon in the presence of oxygen to sulfur in the stochiometnsch necessary amount oxidize The sulfur deposited on the carbon is oxidized during the regeneration of the activated carbon by extraction with carbon disulfide or aqueous Polysulfide solutions detached from the coal, which on the one hand makes the KoMe reusable is, on the other hand, the sulfur m a usable Shape can be regained

The catalytic oxidation of hydrogen sulfide The presence of alkaline substances on activated charcoal is much more beneficial

An alkaline reaction will occur on the surface achieved in that the activated carbon is diluted with Alkali hydroxide solution is impregnated or that an alkaline reacting salt solution on the carbon layer, ζ B of ammonium sulfide, or that the gas containing hydrogen sulfide is applied the treatment on the activated carbon gaseous ammonia in an amount of 0.1 to 1% of the exhaust air is added

In the German patent specification 435 013 a method is also described according to which carbon disulfide and hydrogen sulfide from industrial exhaust air at the same time and together on the same Activated carbon can be deposited, the regeneration being carried out in the manner described above is, if required by the loading condition of the coal

This working method, which at first appears to be very advantageous, has, strangely enough, been found in the industrial practice cannot prevail The viscose producing and processing industry, for which remove the hydrogen sulfide and carbon disulfide from the exhaust air Synonymous for air hygiene and economic reasons is, used to this day two-stage processes, in which first the hydrogen sulfide by means of an alkaline washing solution, which regenerates hydrogen sulfide or releases elemental sulfur, is washed out and then the carbon disulfide by adsorption of activated carbon is withdrawn from the exhaust air and a device for separating hydrogen sulfide and carbon disulfide industrial exhaust air

Applicant

Metallgesellschaft Aktiengesellschaft,

Frankfurt / M, Reuterweg 14

Named as the inventor

Dipl -Chem Dr Helmut Ruping,

Bad Homburg ν d Hohe,

Wendlin Vollmer, Frankfurt / M.,

Dr Karl Bratzier, Bad Homburg ν d Hohe,

Dr Klaus Storp, Dr Erich Herrmann,

Leo Weck, Frankfurt / M.

surprisingly found that the loading capacity an activated carbon layer for the adsorbed carbon disulfide on the one hand and for the through Oxidation of the hydrogen sulfide formed elemental sulfur on the other hand in a complicated way Manner depends on the process conditions of the hydrogen sulfide oxidation, in particular of the excess oxygen present

If there is a high excess of oxygen, as in the exhaust air is always given and with increasing alkali content of the activated carbon and / or the cleaning agent Raw gas leads to the oxidation of the hydrogen sulfide beyond the elemental sulfur to the alkali salts of the oxygen-containing acids of sulfur, in particular to alkali sulphate and alkahthiosulphate, and these salts block the active surface of the activated carbon for both hydrogen sulfide oxidation as well as for carbon disulfide substance adsorption. The higher the alkali content of the activated carbon or the exhaust air, the faster it spreads over the entire height of the activated carbon layer the loading of sulfates and thiosulfates from and makes the activated carbon ineffective more or less quickly depending on this spread The absorption capacity of the activated carbon is therefore in an undesirable side reaction caused by the high excess of oxygen is consumed This determines the frequency of regeneration

However, this will lead to the oxidation of hydrogen sulfide required alkalinity by adding very much

709 610/447

3 4

small amounts of carbon disulfide that were previously considered ineffective are regenerated.

Ammonia is set in the exhaust air, then the ren is resting in a plurality of adsorbers with

Formation of sulfates and thiosulfates almost entirely in the activated carbon layers, of which little-

underpressured The loading of the coal with elementary adsorber in the loading stands while

tarem sulfur progresses from the point of entry of the 5 the remaining adsorber by desorption, extraction,

Raw gas slowly progresses through the activated carbon, with drying and cooling being regenerated, duichge

eme sharply delimited activated carbon layer, which leads to the inventive method is thereby

contain more than 70% of their weight in sulfur characterized that the exhaust air with an NH, -Ge-

The remaining height of the activated carbon bed is below 0.02 percent by volume, preferably 0.005

remains fully absorbent for carbon disulfide io to 0.015 percent by volume, through the in the load

If the oxygen content in the adsorber to be treated is in a known manner from below Gas exceeds the concentration that is passed up to the oxy- that for extraction of the dation of hydrogen sulfide to sulfur sulfur from the activated carbon of the carbon disulfide is necessary, then the alkali concentration is the substance in the adsorber in the extraction which are present in the gas as ammonia at the same time 15 through the entire activated carbon bed or not required, critically ren sulfur-containing part from top to bottom

From hydrogen sulfide and carbon disulfide is passed and that the vaporous sulfur-containing exhaust air (10 g CSJNm ³ and 1.5 to carbon desorbate from the desorption 2 g H ₂ S / Nm ³ ) takes an ordinary, non-alkaline adsorber by indirect heat-dissipated activated carbon a maximum of 3% of their weight in exchange with the carbon disulfide and sulfur elemental sulfur on the extract containing the same volume for its evaporation

5% caustic soda alkalizes, it takes 13% of its weight in elementary amounts of ammonia from the precisely dosed addition of such equal exhaust air However, 28 ° / o of its weight of ele- waiting the high oxygen Uber excess on a so mentarem sulfur take when this waste small area tnttsseite be added to the active carbon layer on the Emluft 0.1 volume percent Amm oniak of the raw gas without the formation of Am-will fix the ammonia addition to this exhaust air to only momum salts, so that for the adsorption 0.01% is measured, then the same, not 30 tion of the carbon disulfide, a sufficient alkalized activated carbon can absorb 64% of its weight in adsorbent volume, which for itself takes up elemental sulfur is regenerated, remains available

The clear local separation of the sulfur. The regeneration of the activated carbon with respect to the Hydrogen oxidation and carbon disulfide loading with carbon disulfide takes place in known adsorption in the same activated carbon layer allowed 35 th way by desorption by means of water vapor Well, for each of these processes, as much as possible a gun. The regeneration of that with elemental sulfur The loading height and loading time of the unloaded portion of the activated carbon layer takes place at the same time set by other In the exhaust air in the known manner, by extraction with Viscose producing and processing industry Carbon disulfide from the recovery The ratio of carbon disulfide to 4 ° m is sufficient considering Hydrogen sulphide about 4.1 to 5.1, but can be less than that of carbon disulphide separate extraction of the individual processing of the exhaust air for hydrogen sulfide and as a result processing stages at some points 10 1 to 20.1 er of the high sulfur levels achieved according to the invention Such exhaust air requires a large amount of additive in a narrow area of the activated carbon layer sorbent volume for the recovery of the 45 can em single activated carbon adsorber with the Carbon disulfide When using the hitherto customary layer height up to twenty times with exhaust air known ammomak additives to the raw gas in Kon- laden and with regard to carbon disulfide means concentrations of 0.1 to 1 percent by volume of steam are consumed before the sulphurous but the incomparably smaller proportion of hydrogen sulfide layer on the gas inlet side reaches a height, as a result of its conversion to sulphate and thiosulphate 50 which marked the capacity for carbon disulfide Adsorbent so quickly that for the hch diminishes in the known adsorption system ^ Carbon disulfide is not economically viable in which number of adsorbers rotates More capacity remains The desorption of the alternating between loading and regeneration Carbon disulfide and the extraction of the sulfur can be switched, the number of adsorber rock must then in short time intervals and at 55 and the layer heights of the activated carbon in the same so small loading heights are measured that the vaporous carbon disulfide was allowed The most important reason to be that the substance desorbate is sufficient to remove the carbon disulfide Joint separation of carbon disulfide and that obtained from sulfur extraction Most of the hydrogen sulfide is evaporated from the same activated charcoal extract according to the invention The carbon disulfide produced in each case has so far been regarded as practically impracticable had to be seen containing desorbates prior to condensation

The invention relates to a method for heating a distillation of the solution of sulfur

Joint deposition of carbon disulfide is used in carbon disulfide

and hydrogen sulphide from exhaust air, which reacts almost to the steam consumption of extract processing

tion accelerator ammonia is added to bury 65 exclusively from waste heat.

Activated carbon, which is related to the carbon disulfide In the drawings, the flow diagram of an

with steam, with respect to the water sulphide layer for carrying out the inventive method

Substance formed sulfur by extraction with Fahrens for example and shown schematically

5 6

FIG. 2 shows a modification of the treatment of the adsorber 2 shown in FIG. 1

Provided heat transfer from the vaporous adsorber air contained by em inert gas, the

Desorbate is fed to the heater of the carbon disulfide through line 51, displaces Da-

After distillation, steam is introduced through line 52.

The system essentially consists of the inert gas and vaporous desorbate are transported through sorber 1, 2, 3, 4, 5, the evaporator 6, the heavy the line 53 and a cooler 54 in the line felausschmelzer 7, the separator 8, the storage 24 before the cooler 26 introduced after the full Reservoir 9 for the solution of sulfur in the sulfur expulsion of the carbon disulfide becomes the adcarbon and the storage tank 10 for pure sorber by blowing warm air from below, carbon disulfide ίο dries and chilled and experiences the same

In the scheme, each step of the operation is treated as the adsorber 3

cycle assigned to an adsorber Dei adsorber 1 The solution collected in the memory 9 of

is in the load The blower 11 sucks the sulfur in carbon disulfide is through a pipe

air from the line 12 and presses it through the device 60 by means of the pump 61 to the evaporator 6

Line 13 in the adsorber 1. By means of a metering 15 and then passed through the heat of the through the

device 14 is the exhaust air flow in line 13 radiator 23 directed vaporous desorbate

a small amount of ammonia evaporated from a line 15 from the adsorber 2 The sulfur

mixed in. The carbon disulfide and carbon vapor is conveyed through line 62 to the

Fused hydrogen-free exhaust air leaves the adsorber I cooler 54,

through the line 16 20 from the evaporator 6 is concentrated solution

The adsorber 2 is in desorption, in which sulfur is converted into carbon disulfide by the corpse Carbon disulfide is passed to the sulfur melter 7 by blowing out the steam device 63 and V01 is expelled when the steam is introduced by indirect heating with steam up to above the the air contained in the adsorber is first heated by the melting point of sulfur Inert gas, which is fed to the melter 7 through line 20, is surrounded by a steam jacket 71, repressed. The desorption steam is then given, in which steam em through line 72 the line 21 supplied The inert gas and which is passed and from which vapors and condensate vapor According to the invention, desorbate is fed through line 73 into a condenser 74 the line 22 to the heating element 23 of the evaporator can be derived from the sulfur melter 7 fers 6 and get out of this through the 30, the carbon disulfide vapors are passed through a Line 24 and coolers 25 and 26 to separator 8 Line 75 into the vapor space of evaporator 6

As shown in FIG. 2, the cooler 25 can be conducted as a heat exchanger, in which the heat of condensation of the desorbate is removed indirectly or continuously through a line 76
on a liquid heat carrier, which the warm- 35 The downstream side of the heat exchanger 25 and the following example should inform about the operation of this system
The heating element 23 of the DestiUationsvomchtung 6 flows through in the exhaust air of a viscose processing Betne cycle, is transmitted besides 2 g / m ³ H ₂ S and 10 g / m ⁸ CS ₂ contain these

In this separator, the condensed exhaust air is separated by an activated carbon layer of 2.5 m

Desorbate is passed into an upper aqueous layer and a layer height of 40, with the exception of a residual content

lower layer of carbon disulfide The aqueous of 3 mg / m ³ total sulfur desulphurizes the exhaust air

Phase is derived through line 27 which was prior to its treatment in the activated carbon layer

Carbon disulfide is added through line 28 in the 0.01 volume percent ammonia. About all of them

Memory 10 is transferred 10 hours, the activated carbon layer by coils

The adsorber 3 steals the drying and the cow 45 is _{freed of CS 2} with water vapor, then it is dried and cooled after the desorption of the carbon disulfide and then air or an inert flow is switched back into the exhaust air by means of a fan 30 during this regeneration time gas through a heater 31 in the line 32 to have other adsorbers led the desulfurization of adsorber 3 and printed from bottom to top by adsorber being regenerated. The buildings are repelled by the 50 men.If this adsorber has passed through 16 adsorption and de

The adsorber 4 is in the process of extracting the carbon disulfide-extracted carbon disulfide. From the storage container 10 ßend the carbon disulfide with water vapor is driven out by means of the pump 41 pure carbon disulfide from the activated carbon layer, then it is led through the line 42 to the adsorber 4 and dried and cooled in 55 the activated carbon and closes this through a connection 43 from above to the hch switched back to the exhaust air flow
Abandoned activated carbon layer. The carbon disulfide containing the sulfur during desorption is obtained from the carbon dioxide mixture, the temperature of which is between 80 and 90 ° C through a line 45 to the storage tank 9. 60 contents of the m 16 desorption penodes

The extraction of the sulfur can advantageously be used. Steam is used to reduce the

take place in such a way that the carbon disulfide falling sulfur-containing carbon disulfide to

Substance only evaporates by means of an intermediate floor 44 and is thus freed from the sulfur

Abandoned sulfur-containing activated carbon layer. After this evaporation, a small amount remains

will. 65 carbon disulfide with a sulfur content of

The adsorber 5 is about 50 to 60% behind in the desorption of the sulfur, which is then caused by evaporation carbon, after extraction of the sulfur in the melter 7 with the aid of rock remained in the activated carbon bed. How the live steam is separated from the sulfur

Claims (4)

Claims 1. Process for the joint separation of carbon disulfide and hydrogen sulfide from exhaust air, to which ammonia is added as a reaction accelerator, on activated carbon, which, with respect to the carbon disulfide, is regenerated with steam, with respect to the sulfur formed from the hydrogen sulfide by extraction with carbon disulfide, in a plurality of adsorbers with static activated carbon layers, of which at least one adsorber is in the load, while the other adsorbers are regenerated by desorption, extraction, drying and cooling, characterized in that the exhaust air with an NH ₃ content below 0.02 percent by volume by the Loading standing adsorber is passed in a known manner from the bottom to the top that zui extraction of the sulfur from the activated carbon, the carbon disulfide in the adsorber standing in the extraction is passed through the entire activated carbon bed or its lower sulfur-containing part from top to bottom and that there s vaporous carbon disulfide desorbate from the adsorber as being desorbed by indirect heat exchange with the Carbon disulfide and sulfur-containing extract is used for its evaporation 2. The method according to claim 1, characterized in that the exhaust air with an NH ₃ content of 0.005 to 0.015 percent by volume through the adsorber in the load is passed in a known manner from bottom to top. 3 device for performing the method according to claim 1, consisting of a discontinuous Adsorber system with several alternating between loading and regeneration switchable adsorbers, characterized by an indirectly heated distillation device known per se (6), the heating element of which is in the desorbent drainage (22) of the carbon disulfide desorbent is connected in front of the cooler (25) 4 modification of the system according to claim 3, characterized in that the cooler (25) is designed as a heat exchanger and that a liquid heat carrier in the circuit through the Heat exchanger (25) and the radiator (23) is circulated Documents considered
German Auslegeschnft No. 1 054 071 1 sheet of drawings 709 610/447 7 67 © Bundesdruckerei Berlin