DE3428452A1 - Process and reactor for the catalytic conversion of hydrogen sulphide into elemental sulphur - Google Patents

Abstract

A process is described for the catalytic conversion, in the presence of sulphur dioxide, of hydrogen sulphide contained in a gas stream to give elemental sulphur. The gas stream is preheated and, for the purpose of conversion, passed over a catalyst bed. The vaporous sulphur produced is condensed out by cooling, and the gas stream freed of sulphur compounds is drawn off. So as to keep the pressure loss as low as possible and to reduce the investment and operating cost, while achieving a sulphur yield close to the theoretically possible value, it is proposed to pass the gas stream over a catalyst bed which is operated quasi-isothermally, to cool the catalyst bed internally by means of a cooling medium, to pass the gas stream into a condenser from below after the reaction, to cool the condenser internally and to draw off the sulphur precipitated on the condenser surface in liquid form.

Description

Process and reactor for catalytic conversion

From Hydrogen Sulphide to Elemental Sulfur The invention relates to a process for the catalytic conversion of hydrogen sulfide contained in a gas stream in the presence of sulfur dioxide to elemental sulfur, the gas stream being preheated and passed over a catalyst bed for reaction, the resulting vapor Sulfur condensed out by cooling and the sulfur compounds were removed Gas stream is withdrawn., And a reactor for carrying out the process.

A process step that is often required when processing raw gas streams is the separation of acid gases, including mainly C02, H2S and multicaptans are to be understood. This separation can be done in various ways, for example adsorptive or by washing. It is particularly advantageous if CO2 and the sulfur-containing acid gases are removed separately from the raw gas streams. For this Both chemical and physical washing processes are particularly suitable Way, the latter being given priority in particular when the raw gas flows contain a lot of CO2. The washing that occurs, for example, during washing that is selective for H2S, Contains residual gas fraction enriched with H2S, depending on the sulfur of hydrogen content of the gas stream to be cleaned, usually between 25 and 90 mol.% H2S.

It has long been known to recover sulfur from a gas stream enriched in this way with H2S. This can, for example, according to one of the Claus Reakton based sulfur recovery system (Claus system) happen. The gases containing H2S and SO2, for example, are converted catalytically on catalysis according to the above reaction - if necessary in several stages - to sulfur, which is initially obtained in vapor form and is condensed by cooling and is adsorbed on the catalyst surface and is higher in the case of hot gas desorption as elemental sulfur Purity is obtained (eg Ullmann Encyclopedia of Industrial Chemistry, Process Engineering, Volume 2, 1972, page 614).

The sulfur production is generally from under low Pressurized gas flows carried out. This means that the entire system only should have a low pressure loss. The gas flow to a Claus plant contains as already mentioned, mostly larger concentrations of H2S.

Since this is highly toxic, a compression of the gas is possible avoided, as there is a risk of H2S escaping from e.g. pipes or Apparatus at increased pressure increases significantly. The Claus reaction is, as in given in the equation, exothermic. For this reason, the response should be as close as possible end low temperatures in order to achieve the highest possible sulfur recovery.

When the temperature gets so low that the elemental sulfur increases condenses out of the catalyst, however, the activity of the same decreases rapidly. For that is but in return the amount of sulfur leaving the reactor very low. To recover the sulfur deposited on the catalyst and to regenerate the activity of the catalyst, several of them then cycle through one another replacing catalyst beds are used. These beds are commonly used operated cyclically below the sulfur dew point and above the sulfur dew point. While the time below the sulfur dew point, sulfur is condensed out, during the time Sulfur is evaporated again above the sulfur dew point and in the downstream Capacitor won.

The present invention is based on the object of a method and to design a reactor of the type mentioned so that with minimal Pressure loss and, with a reduction in investment and operating costs, the sulfur yield until it is brought close to the theoretically possible value.

This object is achieved according to the invention in that the gas stream is passed over a quasi-isothermally operated catalyst bed, the catalyst bed is cooled internally by means of a cooling medium, the gas flow after the reaction below passed into a condenser, the condenser is cooled inside and the one on the condenser surface precipitated sulfur is withdrawn in liquid form.

The invention is based on the basic idea, instead of the conventional ones Series of quasi-adiabatic reactors with intercooling a quasi-isothermal Use reactor with after-cooling. This has the advantage that the low Number of apparatus a minimal pressure loss is possible. Because the temperature is within a single reactor to the optimum final temperature for the Claus reaction can be brought, the system is easier to operate, the investment costs decrease drastically, the sulfur yield can in the desired manner close to the theoretically possible value can be brought, whereby at the same time lower expenses incurred for the post-purification of the exhaust gas from the Claus plant. The danger of H2S leakage from the Claus plant is reduced as the number of devices is smaller will. At the same time, maximum steam generation can be achieved through the isothermal reaction can be achieved, which can benefit the economy of the process.

The boiler feed water can, if necessary, be preheated in the sulfur condenser take place when the inlet temperature of the water is such that the vapor pressure over solid sulfur is higher than the partial pressure of sulfur in the gas. Through this at the same time the risk of corrosion for the tubes of the coolant is reduced because the coolant reaches the reactor at a higher temperature.

Another important advantage is that during a system shutdown the reactor can be kept warm by externally supplied steam. This is necessary, otherwise vaporous sulfur will condense out on the condenser surface and inactivated it. Before restarting the plant, the reactor would have to be expensive cleaned, if necessary even the bed replaced. The one kept warm The reactor, on the other hand, can be started up again without any problems, which is an essential Increasing the operational safety of the entire system means. A second parallel Claus system, which is often required for safety, can therefore be superfluous will.

According to the invention, the H2S-containing gas flows through the quasi-isothermal Catalyst bed that is cooled from the inside. Because the effective flow rate of the gas in the reactor is low because of the low pressure loss available has to be, is a churning up of the catalyst bed by a preferably from below to the top directional current not expected. Likewise is a No churning due to pressure surges due to the low total pressure.

The Claus reaction takes place over the catalyst. After this Reaction, the gas is sent to a condenser for sulfur recovery. That Gas flows from the bottom up through a, also - in countercurrent - internally cooled condenser. The counterflow of cooling medium and gas creates a Rectifying effect achieved, so that the sulfur content at the top of the condenser practically corresponds to the proportion due to the vapor pressure in the gas. Because the cooling medium is relatively cold on the head is abandoned, the temperature on the head is very low, so that also sets a low sulfur content in the gas. In practice, the gas outlet temperature from the condenser to a value, preferably 5 to 100 ° C., above the sulfur fixed point can be set.

An entrainment of sulfur droplets, a source of significant sulfur losses and thus from environmental pollution or the reason for expensive post-cleaning steps from the condenser minimal, as these droplets dripping down from further above Liquid sulfur can be caught. The capacitor works in a similar way like the bottoms of a rectification column. If necessary, at the gas outlet of the Condenser a knitted fabric can be built in to get sulfur droplets back.

In addition, a bed can be filled in the condenser may consist of random packings. The fill serves to improve the soil efficiency the rectification effect of the capacitor described above.

At the same time, this further reduces the probability that Sulfur droplets are entrained into the clean gas.

Due to the adsorption of sulfur on the bed, the Sulfur content in the clean gas at least temporarily below the equilibrium value accordingly the vapor pressure can be lowered.

The sulfur content at the outlet from the condenser therefore corresponds practically based on the chemical equilibrium at the exit of the catalyst bed given thermodynamic equilibrium.

Since the thermodynamic equilibrium in addition to the composition of the The raw gas depends primarily on the temperature at the outlet from the catalyst bed, this temperature must be kept as low as possible. The Claus reaction is exothermic and maximum conversion is obtained therefore if possible low temperature. In practice, the lower temperature limit is determined by the sulfur fixed point lays. However, the catalyst can exit below the sulfur dew point operated from the bed, so that the sulfur condenses there on the catalyst.

In contrast to the known processes, however, there is no parallel process here Catalyst bed necessary, because by cyclical heating of the end of the catalyst bed, in particular by reducing the flow of cooling medium, which according to a preferred embodiment of the method according to the invention first the capacitor and then flows through the catalyst bed, through the condenser part, whereby the temperature of the cooling medium at the entrance to the reactor is increased and at the same time the reduced cooling in the catalyst bed also increases the gas temperature at the end of the bed, the sulfur is evaporated from the catalyst and discharged into the condenser. There it is condensed and recovered.

Since the capacitor now has an increased performance compared to normal operation would have to provide could not be sufficient with the reduced amount of cooling medium Sulfur recovery can be achieved unless the condenser was on overcapacity designed. If this is not the case, the invention provides for the head of the condenser to bring in additional cooling medium and thus the cooling effect to practical to use complete sulfur removal.

.nn the sulfur may be completely atalysed rapid increase in temperature can be seen at the exit from the catalyst bed again the flow rate of the cooling medium of the original cooling coil on the Switched to continuous operation, which increases the temperature at the outlet from the catalyst bed drops below the sulfur dew point. This starts the cycle all over again.

This process has the advantage already mentioned that no second parallel catalyst bed is required.

However, the regulations for sulfur recovery are becoming very much set high, a second catalyst bed may need to be installed due to the slightly increased sulfur content in the exhaust gas during the regeneration occurs, caused by the higher reaction temperature at the exit from the catalyst bed and thereby reduced sulfur turnover.

Collects on the separating tray between the catalyst bed and the condenser liquid sulfur dripping from the top of the condenser cooling coils. There the catalyst bed is hotter than the liquid sulfur, the separating tray is heated and with it the liquid sulfur collected on it boiled up. That liquid sulfur contains dissolved hydrogen sulfide, e.g. in the form of polysulfides. By boiling sulfur vapor rises and only comes into contact with gas there, that little Contains H2S. Therefore, only a little H2S can remain in solution in the liquid sulfur. The hot gas rising from the catalyst bed also comes into contact with the liquid sulfur return, which leads to a heat and mass transfer, which promotes the outgassing of H2S from the sulfur droplets. In general it is off For this reason, your own degassing of the liquid sulfur is no longer necessary, as is usually required for the liquid transport of sulfur, for example. By Saving this facility reduces the costs for the entire system.

Due to the good temperature control in the c; uasi-isothermal reactor the risk of sulfur fires is drastically reduced. This is especially true for Decommissioning and recommissioning. Thanks to the internal cooling, it can be done very quickly and reliably set a temperature below 2000C in the catalyst bed in which the sulfur no longer spontaneously ignites. For example, can air can be used to flush the Claus system shortly after the interruption in operation. All we have to do is wait until the cooling medium with clearly below 2000C lying temperature leaves the catalyst bed. After that is the danger from sulfur fires through contact with air is extremely low. The usual cooling of the catalyst bed and Claus plant with expensive inert gas from operating temperature to below 2000C is omitted.

The internal cooling of the catalyst beds and purging with air has opposite the known method with inert gas the advantage of lower costs and that the Decommissioning can be done much faster.

Commissioning can also be accelerated because the catalyst bed can no longer be cooled by the heat exchanger surfaces, but can also be heated. For commissioning, steam or another suitable heating medium is first used passed through the tubes in the catalyst bed and condenser. When the catalyst light-off temperature is reached, the system can be started up directly with process gas. It is not, as previously usual, the system required by passing combustion gases through slowly heat up from the Claus burner.

There should be blockages due to solidification of sulfur in the catalyst bed have shown, e.g. in the event of an emergency shutdown without the possibility of disconnecting the system from Flushing sulfur free can remove these blockages by heating up the catalyst bed can be easily eliminated with the help of a heating medium in the pipes of the bed.

The H2S / SO2 ratio must be in the raw gas to the quasi-isothermal reactor be set to approximately 2/1. If COS and / or CS2 are present in the raw gas, it is advantageous, before passing the gas stream over the cooled part of the catalyst bed hydrolysis of COS and / or CS2 to perform quasi-H2S, in an adiabatic preliminary layer (without cooling coils) to achieve the required to be able to reach a high temperature of approx. 3400C.

In the case of low H2S contents in the gas flow of, for example, less than 10 mol% the H2S oxidation and the Claus reaction can be carried out in one catalyst bed. The range of application is expanded by the internal cooling of the catalyst bed of the process to higher, S-contents.

Since both reactions (Claus and oxidation) are exothermic, plays for Good temperature control in the catalyst bed is essential to the success of the process Role.

Under appropriate conditions - not too high a H2S content, no catalyst poisons in the raw gas that can be destroyed by burning So according to the invention a complete Claus system from preheating of the raw gas, Reactor and condenser exist.

The cooling medium does not always have to go directly from the condenser to the catalyst bed stream. Instead, there is the option of adding the heat of condensation externally use and obtain cooling medium for the catalyst bed from the outside.

In addition, depending on requirements, several cooling media can be used in the catalyst bed can be used. In this way, the temperature profile in the catalyst bed can be optimized. In a special embodiment of this process, it is provided that cold Raw gas is used as a cooling medium for preheating. With the use of various Cooling media can also achieve the following advantages: In the lower part of the In the catalyst bed, higher temperatures can be set, e.g. for COS / CS2 hydrolysis are needed. Steam generated in the catalyst bed can be in the lower part get overheated. Cold raw gas can practically be used as a cooling medium Reaction temperature are preheated.

In some cases it seems appropriate to use the clean gas from the condenser to recover the sulfur components contained in order to achieve a yield of over To achieve 99.9%.

For this purpose, it is provided according to the invention that the one emerging from the condenser Pure gas from a preferably catalytic afterburning of the sulfur compounds contained therein to undergo essentially SO21 but also SO3.

The gas from the post-combustion is then sent to a gas scrubber, in which SO2 is selectively obtained with a high concentration. The purified gas, which leaves the laundry afterwards is of sulfur compounds to a minimum Exempt residual contents. The SO2 obtained is then advantageously used before the process according to the invention Reactor or returned to a conventional Claus plant.

Such a method not only has the consequence that one with conventional Systems achieved hardly any sulfur recovery, or only achieved with great effort will; it is also shown that the control behavior is very much improved.

As long as the mixture of the gas from the Claus burner and the recycled SO2 has a certain H2S excess, the system regulates itself without any problems itself, i.e.

an exact setting of the H2S: SO2 ratio for the reactor not necessary. The reason for this is that all of them have not been implemented Sulfur compounds burned, washed out and recycled in the plant to form S02 will. In this way, more SO2 gets in front of the reactor and balances the original one H2S excess from.

The vulnerable air control - as in conventional Claus systems is required - can therefore be done here by a simple and even relatively imprecise Proportional control can be replaced before the Claus burner, without thereby the Plant efficiency drops.

The invention also relates to a reactor for carrying out the Process with a gas supply line for the raw gas to be treated, a gas discharge line for sulfur-free gas and a catalyst bed. Significantly is this reactor is designed quasi-isothermally, has a catalyst bed and a condenser on and cooling coils in the catalyst bed and in the condenser.

According to a preferred embodiment, the reactor according to Art of a wound tube bundle heat exchanger with a winding core tube, wherein the coiled tubes serve as cooling coils for the cooling medium and the catalyst bed is arranged in the lower part of the outer space of the core tube.

In practice it has been found that the reactor according to the invention can be used for various exothermic reactions, the catalyst wear compared to conventional fixed bed reactors is lower. Likewise is the occurring Lower pressure loss compared to conventional reactors.

Furthermore, the reactor can be designed so that the cooling coils are connected to one another in the condenser and catalyst bed. This connection can for example be given via the winding core tube.

According to a further embodiment of the reactor can in the Condenser additional cooling coils can be arranged. The same goes for that Catalyst bed in which several cooling coils can also be arranged.

In addition, an adiabatic one is preferred for the hydrolysis COS and / or CS2 to H2S active catalyst layer provided.

In some cases it may also be necessary to have a reactor and a condenser to be separated, e.g. in order to achieve better buildability and transportability. In such a case, the flow through the catalyst bed is from top to bottom possible, possibly also a horizontal flow.

When the Claus reaction is limited by the formation of sulfur and not through the final catalyst temperature, several reactors can be connected in series will. The first catalyst bed is preferably conventional with an external one Sulfur condenser, the last bed, however, designed according to the invention.

This arrangement should be chosen for the following reasons. In the first reactor good adjustment of the chemical equilibrium is not absolutely necessary, so that conventional construction is sufficient.

In the first condenser, maximum sulfur removal is not so critical, so that a conventional construction is sufficient there. The last bed has to be be driven at the lowest possible temperature, preferably below the sulfur dew point, what is possible with the proposed method in one instead of two beds, and Sulfur droplets must be retained as completely as possible at the lowest possible temperature become, which is better feasible with the capacitor proposed here than with conventional construction.

The sulfur obtained in the first condenser contains a lot of H2S, that was in equilibrium with gas still containing H2S.

This sulfur can in the upper part of the condenser according to the invention to be abandoned. There it increases the return and thus improves the recovery from rising, vaporous sulfur. At the same time the H2S-containing sulfur becomes degassed.

It is possible that in the proposed reactor its material must be higher temperature resistant than with conventional construction, because a brick lining of the Claus reactor with Internal cooling only possible with great effort is. For this, however, the number of devices required is lower than with conventional ones Reactors. The control of sulfur fires is easier due to the internal cooling, as low temperatures can be set quickly and safely, in a controllable manner, in which sulfur no longer ignites.

In the following, the method according to the invention is based on a in five figures illustrated embodiment explained in more detail.

They show: FIG. 1 reactor according to the invention of the simplest embodiment FIG. 2 reactor with adiabatic layer for COS / CS2 hydrolysis. FIG. 3 reactor with additional Cooling of the catalyst bed Figure 4 reactor with raw gas preheating.

FIG. 5 Process scheme In the reactor 1 according to FIG. 1 there is a catalyst bed 2 and a capacitor part 3 are arranged. The reactor is preferably as wound tube bundle heat exchanger with a winding core tube 4. the Tube bundles serve as cooling coils 5 in the condenser or 6 in the catalyst bed, which can be connected to each other, 7.

With 8 a filler neck with 9 is a drainage neck for the catalytic converter designated. The reactor has a gas feed line 10 for the gas stream to be treated and a gas discharge line 11 for the gas depleted in sulfur compounds. Farther a discharge line 12 for liquid sulfur is provided.

Boiler feed water with a temperature is preferably used as the coolant introduced above 100 ° C into the condenser via line 5 and into the catalyst bed Evaporating boiler feed water with a temperature between 240 and 3200C. In Any other medium can also be heated in the pipes.

The reactor according to FIG. 2 differs from that according to FIG. 1 only in the fact that below the catalyst layer 2 another for the hydrolysis from COS and / or CS2 to H2S active, quasi-adiabatic layer 13 is arranged. According to this embodiment, the cooling coils 5 and 6 are also via the winding core tube 4 connected to a pipe 14.

The reactor according to FIG. 3 has, compared to that according to FIG. 2 or 1 further cooling coils 15, 16, in which further cooling media are heated. For example, boiler feed water can be used in the cooling coils 5, 6 in the cooling coil 15 cold raw gas and in cooling coil 16 steam to be warmed for overheating.

In the exemplary embodiment in FIG. 4, one takes place in the catalyst bed arranged cooling coil 17 a raw gas preheating. Raw gas e.g. from a Claus furnace and the first sulfur condenser is used as a cooling medium, while on 250 bis 3500C and then introduced via line 18 into the catalyst bed.

FIG. 5 shows an example for the treatment of a Claus gas. Like a conventional system, the system consists of a Claus burner 19 with Waste heat boiler, a first sulfur condenser 20 and a reheating over Bypass line 21 and according to the invention from an internally cooled 22, isothermal Claus reactor 23 with adiabatic pre-bed for COS / CS2 hydrolysis and a second sulfur condenser 24.

68 mol / sec acid gases with a temperature of 300C and a pressure of 2 bar are via line 25 from z. B.

a methanol scrub into the Claus burner. The sour gas has the following composition: N2 2.94 mol% CO2 47.02 molE CH3OH 0.09 mol% H2S 48.27 mol% COS 1.68 mol% In the Claus burner, the acid gas is partially burned, Cooled in the waste heat boiler and liquid sulfur in the first sulfur condenser withdrawn via line 26.

The reheating of the gas in line 27 takes place via a hot bypass 21, to the temperature of about 3400C. The gas then enters the reactor 23 according to the invention.

First, COS and CS2 are hydrolyzed in an adiabatic preliminary work. The gas then enters the part cooled with boiler feed water via line 22 the bed, where practically only the Claus reaction takes place. The temperature at the outlet of the cooled bed is at 260 "C. The temperature has improved Comparability selected as high as a conventional Claus system. By Lowering the temperature, in particular by means of a sub-dewpoint procedure, can of course be done increase the sulfur recovery considerably. According to the invention, there are none for this additional equipment required, in contrast to the conventional Claus system.

Part of the temperature is at the inlet of the cooled bed 370 ° C. The temperature increase compared to the entry temperature into the adiabatic bed is a consequence of the hydrolysis and Claus reaction. Inside the cooled bulk At first there is a steep temperature profile that flattens out towards the end of the bed a. At the end of the bed the temperature is just so high that no liquid sulfur condensed out.

The gas leaves the cooled bed and enters the second Sulfur condenser 24. There the gas is discharged in countercurrent to boiler feed water Line 28 cooled, as a result of which liquid sulfur condenses out, which via line 29 is withdrawn. Clean gas leaves the sulfur condenser at the top (line 30). The clean gas (132.94 mol / sec at 1.6 bar and 1200C has the following composition: N2 49.64 mol% CO2 24.83 mol% H2S 1.57 mol% S02 0.81 mol% COS 260 ppm CS2 65 ppm Sulfur 27 ppm H20 23.11 mol% The sulfur drawn off (3.84 mol / sec) has at 1500C and 1.6 bar the composition: N2 19 ppm CO2 190 ppm H2S 170 ppm S, 99.91 mol% H2O 320 ppm With this variant without sulfur degassing in the second sulfur condenser the sulfur recovery is 90.3% i.e.

it is practically the same size as a two-stage conventional one Claus plant (91.8%, 8% sulfur recovery).

The amount of sulfur obtained is 85.2 t / day.

Accordingly, a reactor according to the invention has approximately the same performance as in a conventional Claus plant, the following apparatus: 1. Claus reactor; 2. Sulfur- capacitor; Reheating through indirect heat exchange, 2. Claus reactor and 3. sulfur condenser.

The advantages of the reactor according to the invention are in terms of simplicity, low space requirement, reduced engineering effort due to the small number of devices and regulations, reduced investment costs evident.

In a second variant, the process is identical to the one before however, the sulfur product from the first condenser is direct for degassing via the line 31 shown in dashed lines in the upper part of the invention Abandoned sulfur condenser.

While in the total sulfur product of the above-described variant 1 a The H2S content is similar to that in the conventional process, namely approx. 170 ppm to 200 ppm because most of the H2S in sulfur comes from the sulfur of the first Condenser originates, the H2S content according to variant 2 is only 12 ppm. This a good degree of desulfurization is achieved in particular by the fact that the sulfur degassing starts practically immediately and not only after a long period of sulfur storage in the -Pit, as is usually done.

Claims (22)

Claims 1. A method for the catalytic conversion of in one Gas stream containing hydrogen sulfide in the presence of sulfur dioxide to elemental Sulfur, in which the gas stream is preheated and converted over a catalyst bed passed, the resulting vaporous sulfur is condensed by cooling and the gas stream freed from sulfur compounds is withdrawn, characterized in that that the gas stream is passed over a quasi-isothermally operated catalyst bed, the catalyst bed is cooled internally by means of a cooling medium, the gas stream after the reaction is passed into a condenser from below, the condenser internally cooled and the sulfur precipitated in the condenser is drawn off in liquid form will. 2. The method according to claim 1, characterized in that the gas stream is passed from the bottom up over the catalyst bed. 3. The method according to claim 1 or 2, characterized in that the Gas outlet temperature at the top of the condenser is set so that the vapor pressure over solid Sulfur is higher than the partial pressure of sulfur in the gas. 4. The method according to any one of claims 1 to 3, characterized in that that the gas outlet temperature to a value between 5 and 10 ° C above the sulfur fixed point is set. 5. The method according to any one of claims 1 to 4, characterized in that that the condenser and the catalyst bed are cooled by the same refrigerant and that the coolant first passes through the condenser and then through the catalyst bed is directed. 6. The method according to any one of claims 1 to 5, characterized in that that the catalyst bed operated cyclically below and above the sulfur dew point and this by reducing or increasing the flow rate of the coolant is effected. 7. The method according to claim 6, characterized in that the head of the condenser is cooled by the use of an additional coolant. 8. The method according to any one of claims 1 to 7, characterized in that that a temperature of 125 to 4500C is maintained in the catalyst bed. 9. The method according to any one of claims 1 to 8, characterized in that that the catalyst bed and the condenser are flushed free by means of air. 10. The method according to any one of claims 1 to 9, characterized in, that in the presence of COS and / or CS2 in the gas stream before the gas stream is introduced about the chilled th part of the catalyst bed a hydrolysis of COS and / or CS2 to H2S carried out in an adiabatic preliminary layer of the catalyst bed will. 11. The method according to any one of claims 1 to 10, characterized in, that sulfur to be degassed from an external source in the upper part of the condenser abandoned, there used as a return and is degassed at the same time. 12. The method according to any one of claims 1 to 11, characterized in that that several coolants are used in the catalyst bed. 13. The method according to claim 12, characterized in that for preheating cold gas is used as a coolant. 14. The method according to any one of claims 1 to 13, characterized in, that the pure gas exiting the condenser is an afterburning of the contained Sulfur components are subjected to SO2. 15. The method according to claim 14, characterized in that the at the afterburning resulting S02 is recycled upstream of the catalyst bed. 16. Reactor for performing the method according to one of the claims 1 to 15 with a gas supply line for the gas to be treated, a gas discharge line for low-sulfur gas and an outlet for liquid sulfur as well as a catalyst, characterized in that the reactor is designed quasi-isothermally that in the Reactor, the catalyst bed and a condenser are arranged and that each Cooling coils are arranged in the catalyst bed and in the condenser. 17. Reactor according to claim 16, characterized in that the reactor designed in the manner of a wound tube bundle heat exchanger with a winding core tube is, the coiled tubes serve as cooling coils for the cooling medium and the catalyst bed is arranged in the lower part of the outer space of the core tube. 18. Reactor according to claim 16 or 17, characterized in that the cooling coils in the condenser and reactor are connected to one another. 19. Reactor according to one of claims 16 to 18, characterized in that that additional cooling coils are arranged in the condenser. 20. Reactor according to one of claims 16 to 19, characterized in that that several cooling coils are arranged in the catalyst bed. 21. Reactor according to one of claims 16 to 20, characterized by an adiabatic catalyst layer that is active for the hydrolysis of COS and / or CS2 to H2S. 22. Reactor according to one of claims 16 to 21, characterized in that that the capacitor has at least one bed.