LU103152B1 - Chemical plant and process for hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream - Google Patents

Abstract

The invention relates to a chemical plant (1) for hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream (17), comprising a hydrofiner (18) for producing a desulfurized product stream (20) and a hydrogen sulfide-containing by-product stream (8) from the feedstock stream (17) with the addition of a hydrogen-containing gas stream (25), a reactor (2) downstream of the hydrofiner (18) for dissociating hydrogen sulfide contained in the hydrogen sulfide-containing by-product stream (8) into the components hydrogen and sulfur to produce a dissociated stream (9), and a first separation device (19) downstream of the reactor (2) for separating sulfur from the dissociated stream (9) to produce a sulfur-containing stream (10) and a residual stream (23), wherein the reactor (2) has an electrically heated reaction chamber (5) for the thermal dissociation of the hydrogen sulfide. and the chemical plant (1) has a first return line (24) by means of which the residual stream (23) can be at least partially returned to the hydrogen-containing gas stream (25), as well as a process for hydrodesulfurizing a hydrocarbon- and sulfur-containing feedstock stream (17).

Description

191930P00LU

LU103152

Chemical plant and process for hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream

State of the art

The invention relates to a chemical plant for hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream according to the preamble of claim 1, as well as a

Method according to the preamble of claim 11.

Fossil fuels, such as oil or natural gas, contain varying degrees of

Sulphur compounds that are oxidized during combustion. Since sulphur oxides are toxic, cause environmental damage and can also damage catalysts, fossil fuels are desulfurized before they are used in order to reduce the sulphur content to a specified standard value. A frequently used method for desulfurization is so-called hydrodesulfurization, in which the sulphur compounds contained in the fossil fuels are

Sulphur compounds are hydrogenated to hydrogen sulphide using hydrogen and separated from the desulfurized product stream. The separation of the sulphur compounds takes place in the so-called hydrofiner in a heterogeneously catalyzed reaction with

Hydrogen to hydrogen sulfide at temperatures of 300-400 °C.

Due to the still very high demand for fossil fuels,

Hydrodesulfurization, especially for the production of fuels in refineries, large

Amounts of hydrogen are required. The hydrogen is currently mainly produced from fossil raw materials using energy-intensive processes, namely steam reforming of natural gas (grey hydrogen). This process has a

CO2 footprint in the range of about 9-12 tCO2/tH2 depending on the feedstock.

The hydrogen demand in refineries and thus the amount of hydrogen sulphide produced is increasing due to the increasing sulphur-containing fossil sources. The amount of hydrogen sulphide produced in the oil processing industry is more than 60 million tonnes per year. According to the conventional route, the hydrogen sulphide is further processed by oxidation at temperatures of 800-1500 °C in the so-called Claus process. This produces elemental sulphur as a valuable product. The hydrogen originally introduced into the process chain is oxidised to water.

191930P00LU

LU103152

There are also increasing efforts in the oil processing industry to improve sustainability and reduce emissions of climate-damaging gases such as carbon dioxide. One approach is to at least partially recover the hydrogen from the hydrogen sulphide.

Such a process for hydrogen production is known, for example, from US 4 481 181 A. Hydrogen is produced from hydrogen sulphide by

Reaction zone the partial oxidation of hydrogen sulphide to water and sulphur is coupled with the thermal decomposition of hydrogen sulphide to hydrogen and sulphur. When one mole of hydrogen sulphide is burned under stoichiometric

In the absence of oxygen, the exothermic partial oxidation generates sufficient heat energy to cause the thermal dissociation of about two moles of hydrogen sulfide.

The hydrogen is captured for use as fuel, and the hydrogen sulfide remaining in the reaction mixture is returned to the incoming gas stream.

The disadvantage is that the known method still requires at least one third of the

hydrogen content is oxidized to water and thus consumed. In addition, the oxidation creates contamination through sulfur oxides.

disclosure of the invention

The object of the invention is therefore to provide a chemical plant and a process for the hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream, which operate cost-effectively and with low maintenance and at the same time have an improved CO2 balance.

This object is achieved by a chemical plant having the features of claim 1.

This will create a chemical plant for the hydrodesulfurization of a hydrocarbon and sulfur-containing feed stream. The chemical plant includes a hydrofiner for producing a desulfurized product stream and a hydrogen sulfide-containing

by-product stream from the feed stream with the addition of a hydrogen-containing gas stream. The chemical plant also includes a downstream hydrofiner

Reactor for dissociating hydrogen sulphide contained in the hydrogen sulphide-containing by-product stream into the components hydrogen and sulphur to produce a dissociated stream, and a first separating device downstream of the reactor for separating sulphur from the dissociated stream to produce a sulphur-containing stream and a residual stream. According to the invention, the reactor

191930P00LU . . 4 . . . . LU103152 for the thermal dissociation of hydrogen sulphide, an electrically heated reaction chamber. The chemical plant has a first return line, by means of which the

Residual stream can be at least partially recycled into the hydrogen-containing gas stream.

For the thermal dissociation of hydrogen sulphide into its components hydrogen and

Sulfur, the reactor comprises the reaction space in which the dissociation of hydrogen sulphide takes place according to the reaction equation

H,S <— H, + S. The reaction enthalpy for this reaction is:

AHR piss = 20.4 kJ/mol.

It is noteworthy that this value is only about half of the reaction enthalpy underlying the steam reforming of methane:

AHg rer = 41.3 kd/mol.

This means that the energy requirement for hydrogen production during the dissociation of hydrogen sulphide is advantageously considerably lower than in the steam reforming of methane.

Due to the special feature of the chemical plant according to the invention that the

Reaction chamber is electrically heated, the energy required to heat the reaction chamber is provided in the form of electrical current. Instead of burning other fossil fuels or hydrogen sulphide produced from fossil fuels, as is known from the state of the art, the required reaction enthalpy can thus be provided partly or completely from electricity generated from renewable sources, which improves the CO2 balance. In addition, the electrical heating of the

reaction chamber has the advantage over other approaches to the dissociation of hydrogen sulphide that this type of heating is both cost-effective and low-maintenance, since the heating is carried out via a constant temperature over its operating life.

electrical circuit and is therefore only subject to very little wear and tear.

191930P00LU

The chemical plant according to the invention has the further advantage that the hydrogen used for hydrodesulfurization is basically recovered almost completely. Apart from lost quantities that are discharged from the plant via other product streams, no hydrogen is required in the chemical plant according to the invention for the recovery of hydrogen.

Hydrogen is consumed. This means that the chemical plant can be operated largely independently of hydrogen, so that the plant can also be operated at locations where no steam reforming plant or other hydrogen source with comparable capacity is available.

Furthermore, the recycling of the hydrogen-containing residual stream into the hydrogen-containing gas stream according to the invention has the advantage that the hydrogen of the residual stream does not have to be laboriously processed and freed from impurities by hydrogen sulphide, as would be necessary for other uses of hydrogen as an energy carrier.

The proportion of non-dissociated hydrogen sulphide in the residual stream is then

Reactor again subjected to thermal dissociation.

In preferred embodiments, the first separating device comprises a cooling section.

The sulphur contained in the dissociated stream can be thermally separated from the remaining gaseous components of the stream by condensation via the cooling section. The cooling section can contain a heat exchanger between the dissociated stream and the by-product stream in order to

The cooling section preferably contains a quench for the sudden cooling of the dissociated stream in order to suppress recombination of the hydrogen and sulphur components to form hydrogen sulphide.

Preferably, the chemical plant comprises, in addition to the first separation device, a second

Separation device for separating non-dissociated residual hydrogen sulphide from the dissociated stream or the residual stream. The second separation device can therefore be connected to the first

The second separation device can be connected upstream or downstream, with the downstream arrangement being preferred. The second separation device is connected to a second return for returning the residual hydrogen sulphide to the reactor. A second separation device is particularly advantageous when the reaction conditions in the reactor produce a significant proportion of non-dissociated hydrogen sulphide in the dissociated stream. The separation then enables an increase in the capacity of the chemical plant with regard to hydrodesulfurization, since the hydrogen sulphide component, which is inert in the hydrofiner, is reduced. The second separation device can, for example, be a pressure swing

adsorption or membrane separation.

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LU103152

In preferred embodiments, the reaction chamber contains a solid material and the reactor is designed to conduct an electric current through the solid material for resistive heating of the reaction chamber. This is achieved by applying an electric field to the solid material. The properties of the solid material and the parameters of the electric field are to be selected for effective resistive heating so that sufficient power loss is generated for heating in the reaction chamber. Due to the power loss, which occurs due to the electrical resistance of the solid material, the electrical energy introduced into the reaction chamber via a power supply is dissipated into thermal energy and thus leads to heating of the solid material. When using electrical energy from renewable sources, the

Extraction of hydrogen as a by-product in the production of sulphur from hydrogen sulphide in a CO2-neutral manner.

Furthermore, the solid material can preferably be selected from the group of carbon, metals, carbides or nitrides. Since the thermal dissociation of hydrogen sulphide is an equilibrium reaction and at high temperatures towards the side of the components

Hydrogen and sulphur are displaced, it is advantageous for a high degree of dissociation and thus for efficient process management if high temperatures prevail in the reaction chamber. The materials mentioned are characterized by an extraordinary heat resistance and are also inert with regard to the dissociation reaction.

It is also advantageous if the solid material has a catalytically active coating. Equipping the solid material with a catalytically active coating has the advantage that, if the kinetics of dissociation are limiting, higher conversions can be achieved, so that the economic efficiency of the chemical plant can be improved. Catalytically active coatings can in particular help to achieve higher degrees of dissociation at the same temperature in the reaction chamber.

In preferred embodiments, the reaction space can be delimited by at least two electrodes arranged at a distance from one another and the solid material can be formed by an electrically conductive particle bed. Particle beds as solid material have the advantage that the heated material also has a large surface area for the dissociation reaction. The large surface area optimizes the process control and reduces the required heated reaction volume. In addition, particle beds offer the advantage of being easy to replace, for example for processing.

191930P00LU to remove any catalytic coating that may be present or to remove sulphur-containing deposits.

The particle bed can, for example, be designed as a fixed bed.

In a further development of the chemical plant according to the invention, the reactor is equipped with a conveying device for the continuous supply and removal of particles from the particle bed in order to form a moving bed. With such a design of the further developed chemical plant according to the invention, the heat can be integrated in a lower reaction zone from the particle bed to the incoming gas stream and in the upper reaction zone from the gas phase to the particle bed. This makes sense in particular if the reverse reaction has sufficient inertia to integrate the heat.

The moving bed design is particularly suitable when the advantage of integrating the heat within the reactor outweighs the additional effort required for recycling the solid particles and the equilibrium shift. This design is also suitable for the continuous regeneration of the solid material, for example in the event of deposits that may occur.

Embodiments in which the particle bed is designed as a fluidized bed are also conceivable. A fluidized bed results in a more homogeneous temperature distribution in the reaction chamber compared to a design of the particle bed as a fixed or moving bed.

This in turn allows the thermal dissociation of hydrogen sulphide to take place as efficiently as possible at a specific, optimised temperature in the entire reaction chamber. In the case of a particle bed designed as a fluidised bed, the electrical heating can be carried out inductively, for example.

In alternative embodiments, the solid material may be formed as a solid with an open-cell foam structure or a lattice structure. Open-cell

Foams and lattice structures form resistively heatable solid bodies with a large surface-to-volume ratio, through which the reaction gases can flow.

According to the process, the object is achieved by a process for hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream, which comprises the following process steps: e generating a desulfurized product stream and a hydrogen sulfide-containing by-product stream from the feedstock stream with the addition of a hydrogen-containing gas stream in a hydrofiner,

191930P00LU e generating a dissociated stream by dissociating hydrogen sulfide contained in the sulfur-hydrogen-containing by-product stream into the components hydrogen and sulfur in a reactor downstream of the hydrofiner and e generating a residual stream by separating sulfur from the dissociated stream in a first separation device.

According to the invention, the dissociation of the hydrogen sulphide takes place thermally in an electrically heated reaction chamber of the reactor and the residual stream is at least partially returned to the hydrogen-containing gas stream via a first return.

The process according to the invention realizes the advantages previously described for the chemical plant according to the invention, which is suitable for carrying out the process.

Preferably, it can be provided that the reaction mixture is cooled in a cooling section of the first separation device, wherein the cooling section particularly preferably has a

Quench. The abrupt cooling suppresses the reverse reaction to hydrogen sulphide and increases the proportion of the desired products, hydrogen and sulphur.

Furthermore, preferably non-dissociated hydrogen sulphide can be separated from the dissociated stream or from the residual stream in a second separation device and fed back into the reactor in order to thereby increase the proportion of products produced.

The reaction chamber is preferably heated resistively by passing an electric current through a solid material arranged in the reaction chamber.

According to the process according to the invention, the temperature in the reaction chamber of the reactor is preferably set to a value in the range from 1200 °C to 1600 °C.

In this way, the equilibrium of dissociation is shifted to the product side and the proportion of product gases produced is maximized. In addition, the reaction rate can be increased by choosing a temperature in the range of 1200 °C to 1600 °C.

Further advantageous embodiments can be found in the following description and the subclaims.

191930P00LU

The invention is described below with reference to the figures LU103152

Examples of implementation are explained in more detail.

Short description of the drawings

Fig. 1 shows schematically a first embodiment of the inventive

Chemical plant with a hydrofiner, a reactor for the thermal dissociation of hydrogen sulphide and a separation device for the separation of sulphur, wherein the remaining residual stream is at least partially returned to the hydrogen-containing gas stream via a first return,

Fig. 2 shows schematically a second embodiment of the inventive

Chemical plant, which additionally has a second separation device for the separation of non-dissociated hydrogen sulphide, which is fed via a second

recirculation is returned to the reactor,

Fig. 3A shows schematically in a sectional view a first embodiment of the reactor for the thermal dissociation of hydrogen sulphide, wherein the reaction space is filled with a particle bed designed as a fixed bed,

Fig. 3B shows schematically the temperature distribution in the reactor according to Fig. 3A in

Operation,

Fig. 4A shows a schematic sectional view of a second embodiment of the reactor for the thermal dissociation of hydrogen sulphide, wherein the reaction chamber is provided with a moving bed

particle bed is filled,

Fig. 4B shows schematically the temperature distribution in the reactor according to Fig. 4A in

Operation,

Fig. 5 shows a schematic sectional view of a third embodiment of the reactor for the thermal dissociation of hydrogen sulphide, wherein the reaction chamber is filled with a solid body with open-cell

foam structure is filled as a heating element.

embodiments of the invention

In the various figures, identical parts are always provided with the same reference symbols and are therefore usually only named or mentioned once.

191930P00LU

Fig. 1 shows schematically a first embodiment of a chemical plant 1 according to the invention for hydrodesulfurizing a hydrocarbon- and sulfur-containing feedstock stream 17. The chemical plant 1 comprises a hydrofiner 18 for producing a desulfurized product stream 20 and a hydrogen sulfide-containing by-product stream 8 from the feedstock stream 17 with the addition of a hydrogen-containing gas stream 25.

In addition to the desulfurized product stream 20, a desulfurized heating gas 21 and/or a hydrogen sulfide-containing condensate 22 can also be produced in the hydrofiner 18, which can be used for crude distillation. The hydrogen-containing gas stream 25 can be added either — as shown — upstream of the hydrofiner 18 or in the hydrofiner itself.

Downstream of the hydrofiner 18 is a reactor 2 for dissociating hydrogen sulphide contained in the hydrogen sulphide-containing by-product stream 8 into the components hydrogen and sulphur to produce a dissociated stream 9 comprising

Hydrogen, sulfur and non-dissociated or recombined hydrogen sulfide. The

Reactor 2 for the thermal dissociation of hydrogen sulphide comprises an electrically heated reaction chamber 5, which is described in more detail below with reference to Figs. 3 to 5.

The reactor 2 is followed by a first separating device 19 for separating sulphur from the stream 9. The separated sulphur is converted into a sulphur-containing

Stream 10 is discharged from the separating device 19. The sulfur is preferably discharged in the liquid phase. A residual stream 23 remains which preferably contains hydrogen and non-dissociated or recombined hydrogen sulfide as the main components.

Finally, the chemical plant 1 has a first recirculation 24, by means of which the residual stream 23 can be at least partially recycled into the hydrogen-containing gas stream 25. The hydrogen-containing gas stream 25 is preferably predominantly derived from the

Residual stream 23 is formed. To compensate for lost quantities of hydrogen that leave the chemical plant 1 via the streams 20, 21, 22 and 10 or are deliberately discharged from the residual stream 23 as gas stream 26, a proportion of hydrogen from another source, for example an electrolysis plant, a methane pyrolysis plant or a steam reforming plant, can also be added to the hydrogen-containing gas stream 25.

191930P00LU

The first separating device 19 can preferably comprise a cooling section 30, which particularly preferably contains a quench. The cooling section 30 serves the purpose of cooling the dissociated stream 9 in order to prevent the reverse reaction of hydrogen and sulfur.

To suppress hydrogen sulphide and to obtain a maximum proportion of the desired products sulphur and hydrogen. A quench offers the advantage of particularly rapid cooling and can be used particularly advantageously as a first element of the cooling section 30.

Fig. 2 shows schematically a second embodiment of a chemical plant 1 according to the invention. The chemical plant 1 according to Fig. 2 differs from the one shown in Fig. 1

embodiment in that it additionally comprises a second separation device 27 for separating non-dissociated residual hydrogen sulphide from the residual stream 23.

The second separating device 27 is provided with a second return line 28 for returning the

residual hydrogen sulfide into reactor 2.

As shown in Fig. 2, the first separation device 19 and the second separation device 27 can be designed as modules connected downstream of a higher-level processing device 29. Embodiments are also conceivable in which the second separation device 27 is connected upstream of the first separation device 19 and non-dissociated residual hydrogen sulfide is first separated from the dissociated stream 9.

Furthermore, the statements regarding the first embodiment according to Fig. 1 apply accordingly to the second embodiment according to Fig. 2.

Figs. 3 to 5 show schematically different embodiments for the reactor 2, as it can be used in the chemical plants according to Figs. 1 and 2.

The reactor 2 has an inlet 3 for the by-product stream 8 and an outlet 4 for the dissociated stream 9. Between the inlet 3 and the outlet 4 is the reaction chamber 5. This reaction chamber 5 is delimited on the outside by a reactor jacket 6, the inside of which is preferably provided with a reactor lining 7. By the

Reactor lining 7 can provide both sufficient thermal insulation and a desired thermal capacity. This can improve both the economic efficiency of the process and - after a heating phase - the constancy of the temperature in the reaction chamber 5 for the thermal dissociation of hydrogen sulphide into the components hydrogen and sulphur.

191930P00LU

In the embodiments shown, the electrically heated reaction chamber 5 contains a LU103152

Solid-state material 11, wherein the reactor 2 is designed to resistively heat the reaction space 5 by conducting an electric current through the solid-state material 11.

The reaction chamber 5 is delimited by at least two electrodes 12, which can be connected to an external power supply for resistive heating of the reaction chamber 5. The electrodes 12 can - as shown - be arranged at a distance from one another in the flow direction of the reactor 2. According to a not shown

However, in this embodiment, the electrodes can also alternatively or additionally be arranged laterally on the inner walls of the reactor.

Heating is achieved by applying an electric field to the solid material 11 using the electrodes 12. The properties of the solid material 11 and the parameters of the electric field are to be selected so that sufficient power loss is achieved.

Heating of the solid material 11 results in a temperature suitable for the thermal decomposition of

Hydrogen sulphide to reach the desired temperature. In this way, the production of hydrogen as a by-product in the production of

Sulfur from hydrogen sulphide is CO2-neutral and can be produced efficiently.

To improve the homogeneity of the temperature distribution in the solid material 11, the electrodes 12 can be designed as a grid or rod electrode structure that contacts the solid material 11 evenly over the entire reactor cross-section. The number of electrodes 12 present is at least two, but can also be any larger number.

The solid material 11 is preferably selected from the group consisting of carbon, metals, carbides or nitrides. The solid material 11 also preferably has a catalytically active coating. The catalytically active coating can reduce the temperature in the reaction chamber required for the thermal decomposition of the hydrogen sulphide. In addition, if the kinetics of the dissociation are limiting, higher conversions can be achieved, so that the economic efficiency of the chemical plant 1 is improved.

The temperature in the reaction chamber 5 for the dissociation of hydrogen sulphide 8 is preferably set to a range from 900 °C to 1600 °C, with the equilibrium being shifted to the product side at higher temperatures. The temperature is particularly preferred

191930P00LU temperature in the reaction chamber 5 of the reactor 2 is therefore set to a value in the range of 1200 °C LU103152 to 1600 °C.

In the two embodiments according to Figs. 3 and 4, the reaction space 5 is delimited by at least two electrodes 12 arranged at a distance from one another and the solid material 11 is formed by an electrically conductive particle bed.

Fig. 3A shows an embodiment in which the particle bed is formed as a fixed bed 13.

Fig. 3B shows the temperature profile resulting during operation in reactor 2 according to Fig. 3A.

After the hydrogen sulphide-containing by-product stream 8 introduced into the reactor via the inlet 3 has reached the inlet 3 with an inlet temperature in the range 20°C to 500°C (possibly achieved by external preheating), the temperature in the reaction chamber 5 increases continuously to a maximum temperature in the range 1000°C to 2000°C.

The product gases produced then leave the reactor 2 via the outlet 4 as a dissociated stream 9 with essentially unchanged temperature. The fixed bed 13 can achieve a CO2-neutral and effective dissociation of hydrogen sulphide, which is advantageously characterized by the fact that when catalytically active coatings are used, the catalyst does not have to be separated from the product compared to reactors with dissolved catalyst, thus eliminating the need for a purification step.

Fig. 4A shows an embodiment in which the particle bed is designed as a moving bed 14. For this purpose, the reactor 2 is equipped with a conveying device 31 for the continuous supply and removal of particles from the particle bed. The particles of the moving bed 14 pass through the reactor 2 preferably in countercurrent to the hydrogen sulfide-containing by-product stream 8.

The temperature profile resulting during operation is shown in Fig. 4B. By guiding the particles of the moving bed 14 in countercurrent to the hydrogen sulphide-containing by-product stream 8, a

Heat integration zone. In the heat integration zone, the inflowing hydrogen sulphide-containing by-product stream 8 can be preheated to at least 800°C by the still hot particles of the moving bed 14 emerging from the reaction chamber 5. The

The temperature depends on the heat transfer between the solid and the gas phase and can be higher depending on the temperature of the solid and the transfer properties. In a first section of the reaction chamber 5, the first reaction zone 15,

191930P00LU then follows a further resistive heating to the desired reaction temperature, LU103152 for example 1500°C. In a subsequent second reaction zone 16 there is an equilibrium between the heat supplied, the reaction energy required and the heat losses, in which the temperature is approximately constant. In the area of the outlet 4 a second heat integration zone is formed in which the heat of the dissociated stream 9 can be partially recovered and passed on to newly flowing particles of the moving bed 14.

In such an embodiment of the reactor 2, the heat can be integrated in the region of the inlet 3 and in the first reaction zone 15 from the particles of the moving bed 14 to the incoming gas stream 8 and in the region of the outlet 4 from the dissociated stream 9 to the particles of the moving bed 14. Furthermore, the embodiment is suitable for the continuous regeneration of the solid material 11; for example, in the event of any deposits that may occur.

Fig. 5 shows a third embodiment of the reactor 2, in which the solid material 11 is designed as a solid 32 with an open-cell foam structure. The hydrogen sulphide-containing by-product stream 8 flows through the pores of the open-cell foam structure from the inlet 3 towards the outlet 4. The hydrogen sulphide is thereby

Solid body 32 dissociates the ohmic heat into hydrogen and sulphur. Instead of an open-cell foam structure, a solid body with a preferably three-dimensional lattice structure (not shown) can also be used.

Otherwise, the statements regarding the first two embodiments apply accordingly.

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List of reference symbols LU103152 1 Chemical plant 2 Reactor 3 Inlet 4 Outlet

Reaction chamber 6 Reactor shell 7 Reactor lining 8 By-product stream 9 Dissociated stream Sulphur-containing stream 11 Solid material 12 Electrode 13 Fixed bed 14 Moving bed First reaction zone 16 Second reaction zone 17 Feed stream 18 Hydrofiner 19 First separation device

Product stream 21 desulfurized heating gas 22 hydrogen sulfide-containing condensate 23 residual stream 24 first recirculation hydrogen-containing gas stream 26 discharged gas stream 27 second separation device 28 second recirculation 29 treatment device

Cooling section 31 Conveyor device 32 Solid body

Claims (15)

191930P00LU 1/3 LU103152 PATENT CLAIMS 1. Chemical plant for hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream (17), comprising a hydrofiner (18) for producing a desulfurized product stream (20) and a hydrogen sulfide-containing by-product stream (8) from the feedstock stream (17) with the addition of a hydrogen-containing gas stream (25), a reactor (2) downstream of the hydrofiner (18) for dissociating hydrogen sulfide contained in the hydrogen sulfide-containing by-product stream (8) into the components hydrogen and sulfur to produce a dissociated stream (9), and a first separation device (19) downstream of the reactor (2) for separating sulfur from the dissociated stream (9) to produce a sulfur-containing stream (10) and a residual stream (23), characterized in that the reactor (2) comprises an electrically heated reaction chamber (5) for the thermal dissociation of the hydrogen sulfide and the chemical plant (1) has a first return line (24) by means of which the residual stream (23) can be at least partially returned to the hydrogen-containing gas stream (25). 2. Chemical plant according to claim 1, characterized in that the first separation device (19) comprises a cooling section (30), which preferably contains a quench. 3. Chemical plant according to claim 1 or 2, characterized in that the chemical plant (1) comprises a second separation device (27) for separating non-dissociated residual hydrogen sulphide from the dissociated stream (9) or the residual stream (23), which is connected to a second return (28) for returning the residual hydrogen sulphide to the reactor (2). 4. Chemical plant according to one of claims 1 to 3, characterized in that the reaction chamber (5) contains a solid material (11) and the reactor (2) for resistive heating of the reaction chamber (5) is designed to conduct an electric current through the solid material (11). 5. Chemical plant according to claim 4, characterized in that the solid material (11) is selected from the group carbon, metals, carbides or nitrides. 191930P00LU 2/3 LU103152 6. Chemical plant according to claim 4 or 5, characterized in that the solid material (11) has a catalytically active coating. 7. Chemical plant according to one of claims 4 to 6, characterized in that the reaction space (5) is delimited by at least two electrodes (12) arranged at a distance from one another and the solid material (11) is formed by an electrically conductive particle bed. 8. Chemical plant according to claim 7, characterized in that the particle bed is designed as a fixed bed (13). 9. Chemical plant according to claim 7, characterized in that the reactor (2) is equipped with a conveying device (31) for the continuous supply and removal of particles of the particle bed in order to form a moving bed (14). 10. Chemical plant according to one of claims 4 to 6, characterized in that the solid material (11) is designed as a solid body (32) with an open-cell foam structure or a lattice structure. 11. Process for hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream (17), comprising the following process steps: generating a desulfurized product stream (20) and a hydrogen sulfide-containing by-product stream (8) from the feedstock stream (17) with the addition of a hydrogen-containing gas stream (25) in a hydrofiner (18), generating a dissociated stream (9) by dissociating hydrogen sulfide contained in the hydrogen sulfide-containing by-product stream (8) into the components hydrogen and sulfur in a reactor (2) downstream of the hydrofiner (18), and generating a residual stream (23) by separating sulfur from the dissociated stream in a first separation device (19), characterized in that the dissociation of the hydrogen sulfide takes place thermally in an electrically heated reaction chamber (5) of the reactor (2) and the residual stream (23) is at least partially returned to the hydrogen-containing gas stream (25) via a first return line (24). 191930P00LU 3/3 12. The method according to claim 11, characterized in that the reaction mixture LU103152 is cooled in a cooling section (30) of the first separation device (19), wherein the cooling section (30) preferably contains a quench. 13. The method according to claim 11 or 12, characterized in that non-dissociated hydrogen sulphide is separated from the dissociated stream (9) or the residual stream (23) in a second separation device (27) and fed back to the reactor (2). 14. Method according to one of claims 11 to 13, characterized in that the reaction chamber (5) is heated resistively by passing an electric current through a solid material (11) arranged in the reaction chamber (5). 15. Process according to one of claims 10 to 14, characterized in that the temperature in the reaction chamber (5) of the reactor (2) is set to a value in the range from 1200 °C to 1600 °C.