Chemical plant and method for a hydrodesulfurization of a hydrocarbon- and sulfur-containing feedstock stream
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- THYSSENKRUPP UHDE GMBH
- Filing Date
- 2024-06-07
- Publication Date
- 2026-04-29
AI Technical Summary
Current hydrodesulfurization processes for fossil fuels are energy-intensive and carbon-heavy, requiring large amounts of hydrogen produced from fossil fuels, which results in significant CO2 emissions and hydrogen sulfide production, while also being costly and requiring frequent maintenance.
A chemical plant and process that includes a hydrofiner for producing a desulfurized product stream and a byproduct stream containing hydrogen sulfide, with a reactor for thermally dissociating hydrogen sulfide into hydrogen and sulfur using an electrically heated reaction space, allowing for partial recycling of the residual stream and reducing energy consumption and emissions by using renewable electricity.
The process significantly reduces energy requirements and CO2 emissions by using renewable electricity for heating, recovers nearly all hydrogen for reuse, and minimizes maintenance, enabling efficient and sustainable hydrodesulfurization with improved CO2 balance and reduced hydrogen consumption.
Smart Images
Figure EP2024065777_26122024_PF_FP_ABST
Abstract
Description
[0001] Chemical plant and process for hydrodesulfurization of a hydrocarbon and sulfur-containing feed stream
[0002] State of the art
[0003] The invention relates to a chemical plant for hydrodesulfurizing a hydrocarbon- and sulfur-containing feed stream according to the preamble of claim 1, as well as to a process according to the preamble of claim 11.
[0004] Fossil fuels, such as crude oil or natural gas, contain varying degrees of sulfur compounds that are oxidized during combustion. Because sulfur oxides are toxic, can cause environmental damage, and can also damage catalysts, fossil fuels are desulfurized before use to reduce the sulfur content to a specified standard. A frequently used desulfurization process is hydrodesulfurization, in which the sulfur compounds contained in the fossil fuels are hydrogenated with hydrogen to form hydrogen sulfide and separated from the desulfurized product stream. The sulfur compounds are separated in the so-called hydrofiner in a heterogeneously catalyzed reaction with hydrogen to form hydrogen sulfide at temperatures of 300–400 °C.
[0005] Due to the still very high demand for fossil fuels, large quantities of hydrogen are required for their hydrodesulfurization, particularly for the production of fuels in refineries. Currently, hydrogen is also predominantly produced from fossil feedstocks using energy-intensive processes, namely steam reforming of natural gas (grey hydrogen). This process has a carbon dioxide (CH) footprint in the range of approximately 9-12 tCO2 / tH2, depending on the feedstock.
[0006] The demand for hydrogen in refineries, and thus the amount of hydrogen sulfide produced, is even increasing due to increasingly sulfur-containing fossil sources. The amount of hydrogen sulfide produced in the oil processing industry is more than 60 million tons annually. According to the conventional route, the hydrogen sulfide is further processed by oxidation at temperatures of 800–1500 °C in the so-called Claus process. This process produces elemental sulfur as a valuable product. The hydrogen originally introduced into the process chain is oxidized to water. The petroleum processing industry is also increasingly striving 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 sulfide.
[0007] Such a process for hydrogen production is known, for example, from US 4481 181 A. In this process, hydrogen is produced from hydrogen sulfide by coupling the partial oxidation of hydrogen sulfide to water and sulfur with the thermal decomposition of hydrogen sulfide to hydrogen and sulfur in a single reaction zone. When one mole of hydrogen sulfide is burned under stoichiometric oxygen deficiency, the exothermic partial oxidation generates sufficient heat energy to cause the thermal dissociation of approximately two moles of hydrogen sulfide. The hydrogen is collected for use as fuel, and the hydrogen sulfide remaining in the reaction mixture is returned to the incoming gas stream. A disadvantage is that in this known process, at least one-third of the hydrogen content is still oxidized to water and thus consumed.In addition, oxidation creates contamination by sulfur oxides.
[0008] Disclosure of the invention
[0009] The object of the invention is therefore to provide a chemical plant and a process for the hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream, which operate cost-effectively and require little maintenance and at the same time have an improved CO2 balance.
[0010] This object is achieved by a chemical plant having the features of claim 1.
[0011] This creates a chemical plant for hydrodesulfurizing a hydrocarbon- and sulfur-containing feed stream. The chemical plant comprises a hydrofiner for generating 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 further comprises a reactor downstream of the hydrofiner for dissociating hydrogen sulfide contained in the hydrogen sulfide-containing by-product stream into its hydrogen and sulfur components to generate a dissociated stream, as well as a first separation device downstream of the reactor for separating sulfur from the dissociated stream to generate a sulfur-containing stream and a residual stream. According to the invention, the reactor comprises an electrically heated reaction chamber for the thermal dissociation of the hydrogen sulfide.The chemical plant has a first recirculation line by means of which the residual stream can be at least partially recycled into the hydrogen-containing gas stream.
[0012] For the thermal dissociation of hydrogen sulphide into its components hydrogen and sulphur, the reactor comprises the reaction chamber in which the dissociation of hydrogen sulphide takes place according to the reaction equation
[0013] H2S H2+ S. The reaction enthalpy for this reaction is:
[0014] AH R,Diss = 20.4 kJ / mol.
[0015] It is noteworthy that this value is only about half of the reaction enthalpy underlying the steam reforming of methane:
[0016] AH R,Ref - 41.3 kJ / mol.
[0017] This means that the energy required to produce hydrogen during the dissociation of hydrogen sulfide is advantageously considerably lower than in the steam reforming of methane.
[0018] 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 electricity. Instead of burning additional fossil fuels or hydrogen sulfide produced from fossil fuels, as is known from the prior art, the required reaction enthalpy can thus be provided partially or entirely from renewable electricity, thereby improving the CO2 balance. Furthermore, electrical heating of the reaction chamber has the advantage over other approaches to dissociating hydrogen sulfide in that this type of heating is both cost-effective and low-maintenance, since the heating is provided via an electrical circuit that remains unchanged over its operating life and is therefore only subject to very little wear.The chemical plant according to the invention has the further advantage that the hydrogen used for hydrodesulfurization is essentially recovered almost completely. Apart from lost quantities that are removed from the plant via other product streams, no hydrogen is consumed in the chemical plant according to the invention to recover the hydrogen. This means that the chemical plant can be operated largely self-sufficiently in terms 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.
[0019] Furthermore, the inventive recycling of the hydrogen-containing residual stream into the hydrogen-containing gas stream has the advantage that the hydrogen in the residual stream does not require complex processing and removal of hydrogen sulfide impurities, as would be necessary for other uses of hydrogen as an energy carrier. The portion of undissociated hydrogen sulfide in the residual stream is subsequently subjected to further thermal dissociation in the reactor.
[0020] In preferred embodiments, the first separation device comprises a cooling section. The sulfur 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 include a heat exchanger between the dissociated stream and the by-product stream to preheat the by-product stream before it enters the reactor. The cooling section preferably includes a quench for abruptly cooling the dissociated stream to suppress recombination of the hydrogen and sulfur components to form hydrogen sulfide.
[0021] In addition to the first separation device, the chemical plant preferably comprises a second separation device for separating non-dissociated residual hydrogen sulfide from the dissociated stream or the residual stream. The second separation device can therefore be arranged upstream or downstream of the first separation device, with the downstream arrangement being preferred. The second separation device is connected to a second recirculation line for returning the residual hydrogen sulfide 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 sulfide in the dissociated stream. The separation then enables an increase in the hydrodesulfurization capacity of the chemical plant, since the hydrogen sulfide component, which is inert in the hydrofiner, is reduced.The second separation device can, for example, comprise a pressure swing adsorption or a membrane separation. In preferred embodiments, the reaction chamber contains a solid material, and the reactor is designed to resistively heat the reaction chamber by conducting an electric current through the solid material. This is achieved by applying an electric field to the solid material. For effective resistive heating, the properties of the solid material and the parameters of the electric field must be selected so that sufficient power loss is generated for heating 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, thus heating the solid material.When using electrical energy from renewable sources, the production of hydrogen as a by-product in the production of sulfur from hydrogen sulfide becomes CO2-neutral.
[0022] Furthermore, the solid material can preferably be selected from the group consisting of carbon, metals, carbides, or nitrides. Since the thermal dissociation of hydrogen sulfide is an equilibrium reaction and shifts toward the hydrogen and sulfur components at high temperatures, it is advantageous for a high degree of dissociation and thus for efficient process control if high temperatures prevail in the reaction chamber. These materials are characterized by exceptional heat resistance and are also inert towards the dissociation reaction.
[0023] 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, in the event that the kinetics of dissociation are limiting, higher conversions can be achieved, thus improving the economic efficiency of the chemical plant. Catalytically active coatings can, in particular, contribute to achieving higher degrees of dissociation at the same temperature in the reaction chamber.
[0024] In preferred embodiments, the reaction space can be defined by at least two spaced-apart electrodes, and the solid-state material can be formed by an electrically conductive particle bed. Particle beds as solid-state material have the advantage that the heated material simultaneously has a large surface area for the dissociation reaction. The large surface area optimizes the process control and reduces the required heated reaction volume. Furthermore, particle beds offer the advantage of easy exchangeability, for example, for reprocessing any existing catalytic coating or for removing sulfur-containing deposits.
[0025] The particle bed can, for example, be designed as a fixed bed.
[0026] 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 to form a moving bed. With such a configuration 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 when the inertia of the reverse reaction is sufficient to integrate the heat. The moving bed embodiment is particularly suitable when the advantage of integrating the heat within the reactor outweighs the additional effort due to the recycling of the solid particles and the equilibrium shift.Furthermore, this design is suitable for the continuous regeneration of the solid material, for example in the event of deposits that may occur.
[0027] Embodiments in which the particle bed is configured as a fluidized bed are also conceivable. A fluidized bed results in a more homogeneous temperature distribution in the reaction chamber compared to a fixed or moving bed configuration. This, in turn, allows the thermal dissociation of hydrogen sulfide to proceed as efficiently as possible at a specific, optimized temperature throughout the reaction chamber. With a particle bed configured as a fluidized bed, electrical heating can be achieved, for example, inductively.
[0028] In alternative embodiments, the solid material can be formed as a solid with an open-cell foam structure or a lattice structure. Open-cell foams and lattice structures form resistively heatable solids with a high surface-to-volume ratio, which can also be permeated by the reaction gases.
[0029] According to the process, the object is achieved by a process for hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream, which comprises the following process steps: • Producing a desulfurized product stream and a hydrogen sulfide-containing by-product stream from the feed stream with admixture of a hydrogen-containing gas stream in a hydrofiner,
[0030] • Generating a dissociated stream by dissociating hydrogen sulphide contained in the hydrogen sulphide-containing by-product stream into the components hydrogen and sulphur in a reactor downstream of the hydrofiner and
[0031] • Generating a residual stream by separating sulfur from the dissociated stream in a first separation device.
[0032] 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 recycled into the hydrogen-containing gas stream via a first recirculation.
[0033] 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.
[0034] Preferably, the reaction mixture can be cooled in a cooling section of the first separation device, wherein the cooling section particularly preferably contains a quench. The abrupt cooling suppresses the reverse reaction to hydrogen sulfide and increases the proportion of the desired products, hydrogen and sulfur.
[0035] Furthermore, preferably non-dissociated hydrogen sulfide can be separated from the dissociated stream or from the residual stream in a second separation device and fed back to the reactor in order to thereby increase the proportion of products produced.
[0036] The reaction chamber is preferably heated resistively by passing an electric current through a solid material arranged in the reaction chamber.
[0037] 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 of 1200 °C to 1600 °C. In this way, the dissociation equilibrium is shifted to the product side, thus maximizing the proportion of product gases produced. Furthermore, the reaction rate can be increased by selecting a temperature in the range of 1200 °C to 1600 °C. Further advantageous embodiments can be found in the following description and the dependent claims.
[0038] The invention is explained in more detail below with reference to the embodiments shown in the attached figures.
[0039] Brief description of the drawings
[0040] Fig. 1 shows schematically a first embodiment of the chemical plant according to the invention 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 recycled via a first recirculation into the hydrogen-containing gas stream,
[0041] Fig. 2 shows schematically a second embodiment of the chemical plant according to the invention, which additionally has a second separation device for separating non-dissociated hydrogen sulphide, which is returned to the reactor via a second recirculation,
[0042] Fig. 3A shows a schematic sectional view of a first embodiment of the reactor for the thermal dissociation of hydrogen sulphide, wherein the reaction chamber is filled with a particle bed designed as a fixed bed,
[0043] Fig. 3B shows schematically the temperature distribution in the reactor according to Fig. 3A during operation,
[0044] 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 filled with a particle bed designed as a moving bed,
[0045] Fig. 4B shows schematically the temperature distribution in the reactor according to Fig. 4A during operation,
[0046] Fig. 5 shows schematically in a sectional view a third embodiment of the reactor for the thermal dissociation of hydrogen sulfide, wherein the reaction space is filled with a solid body with an open-cell foam structure as a heating element.
[0047] Embodiments of the invention In the various figures, identical parts are always provided with the same reference numerals and are therefore usually named or mentioned only once.
[0048] Fig. 1 schematically shows a first embodiment of a chemical plant 1 according to the invention for hydrodesulfurizing a hydrocarbon- and sulfur-containing feed 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 feed stream 17 with admixture of a hydrogen-containing gas stream 25.
[0049] In addition to the desulfurized product stream 20, a desulfurized fuel gas 21 and / or a hydrogen sulfide-containing condensate 22 may also be produced in the hydrofiner 18, which can be used for crude distillation. The admixture of the hydrogen-containing gas stream 25 can take place either—as shown—upstream of the hydrofiner 18 or in the hydrofiner itself.
[0050] Downstream of the hydrofiner 18 is a reactor 2 for dissociating hydrogen sulfide contained in the hydrogen sulfide-containing by-product stream 8 into its hydrogen and sulfur components, producing a dissociated stream 9 comprising hydrogen, sulfur, and undissociated or recombined hydrogen sulfide. The reactor 2 for thermally dissociating the hydrogen sulfide comprises an electrically heated reaction chamber 5, which is described in more detail below with reference to Figs. 3 to 5.
[0051] Downstream of reactor 2, a first separation device 19 is connected for separating sulfur from stream 9. The separated sulfur is discharged from the separation device 19 in a sulfur-containing stream 10. Preferably, the sulfur is discharged in the liquid phase. A residual stream 23 remains, which preferably contains hydrogen and undissociated or recombined hydrogen sulfide as the main components.
[0052] Finally, the chemical plant 1 has a first recirculation line 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 formed predominantly from the residual stream 23. To compensate for lost amounts 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 portion of hydrogen from another source, for example an electrolysis plant, a methane pyrolysis plant, or even a steam reforming plant, can also be admixed to the hydrogen-containing gas stream 25.
[0053] The first separation 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 suppress the reverse reaction of hydrogen and sulfur to form hydrogen sulfide and to obtain a maximum proportion of the desired products, sulfur and hydrogen. A quench offers the advantage of particularly rapid cooling and can be used advantageously, in particular, as a first element of the cooling section 30.
[0054] Fig. 2 schematically shows a second embodiment of a chemical plant 1 according to the invention. The chemical plant 1 according to Fig. 2 differs from the embodiment shown in Fig. 1 in that it additionally comprises a second separation device 27 for separating non-dissociated residual hydrogen sulfide from the residual stream 23. The second separation device 27 is connected to a second recirculation line 28 for recirculating the residual hydrogen sulfide to the reactor 2.
[0055] As shown in Fig. 2, the first separation device 19 and the second separation device 27 can be designed as downstream modules 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.
[0056] Furthermore, the statements regarding the first embodiment according to Fig. 1 apply accordingly to the second embodiment according to Fig. 2.
[0057] Figs. 3 to 5 schematically show various embodiments of the reactor 2 as it can be used in the chemical plants according to Figs. 1 and 2.
[0058] Reactor 2 has an inlet 3 for the by-product stream 8 and an outlet 4 for the dissociated stream 9. Between inlet 3 and outlet 4 is reaction chamber 5. This reaction chamber 5 is bounded on the outside by a reactor shell 6, the inside of which is preferably provided with a reactor lining 7. The reactor lining 7 can provide both sufficient thermal insulation and the desired heat capacity. This can improve both the economic efficiency of the process and—after a heating phase—the constancy of the temperature in reaction chamber 5 for the thermal dissociation of hydrogen sulfide into its components hydrogen and sulfur.
[0059] In the embodiments shown, the electrically heated reaction chamber 5 contains a solid material 11, wherein the reactor 2 is designed to conduct an electric current through the solid material 11 for resistive heating of the reaction chamber 5.
[0060] For this purpose, 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 spaced apart from one another in the flow direction of the reactor 2. However, according to an embodiment not shown, the electrodes can also be arranged laterally or additionally on the inner walls of the reactor.
[0061] Heating is achieved by applying an electric field to the solid material 11 via electrodes 12. The properties of the solid material 11 and the parameters of the electric field must be selected to ensure sufficient power loss for heating the solid material 11 to achieve the desired temperature for the thermal decomposition of hydrogen sulfide. This ensures that the production of hydrogen as a by-product in the production of sulfur from hydrogen sulfide is CO2-neutral and efficient.
[0062] 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 across the entire reactor cross-section. The number of electrodes 12 present is at least two, but can also be any larger number.
[0063] The solid material 11 is preferably selected from the group consisting of carbon, metals, carbides, or nitrides. Furthermore, the solid material 11 preferably has a catalytically active coating. The catalytically active coating allows the temperature in the reaction chamber 5 required for the thermal decomposition of the hydrogen sulfide to be lowered. Furthermore, in the event that the kinetics of dissociation are limiting, higher conversions can be achieved, thus improving the economic efficiency of the chemical plant 1. The temperature in the reaction chamber 5 for the dissociation of hydrogen sulfide 8 is preferably set within a range of 900°C to 1600°C, with the equilibrium being shifted toward the product side at higher temperatures. Therefore, the temperature in the reaction chamber 5 of the reactor 2 is particularly preferably set within a range of 1200°C to 1600°C.
[0064] 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.
[0065] Fig. 3A shows an embodiment in which the particle bed is designed as a fixed bed 13.
[0066] Fig. 3B shows the temperature profile resulting during operation in reactor 2 according to Fig. 3A.
[0067] After the hydrogen sulfide-containing by-product stream 8 introduced into the reactor via inlet 3 has reached inlet 3 with an inlet temperature in the range of 20°C to 500°C (possibly achieved by external preheating), the temperature in the reaction chamber 5 rises continuously to a maximum temperature in the range of 1000°C to 2000°C. Subsequently, the product gases generated leave reactor 2 via outlet 4 as a dissociated stream 9 with essentially unchanged temperature. The fixed bed 13 enables CCh-neutral and effective dissociation of hydrogen sulfide to be achieved, 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, thus eliminating the need for a purification step, compared to reactors with dissolved catalyst.
[0068] Fig. 4A shows an embodiment in which the particle bed is configured 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.
[0069] 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 sulfide-containing by-product stream 8, a heat integration zone forms in the region of the inlet 3 upstream of the first electrode 12. In the heat integration zone, the inflowing hydrogen sulfide-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 temperature depends on the heat transfer between the solid and gas phases and can also 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, further resistive heating to the desired reaction temperature, for example 1500°C, then takes place.In a subsequent second reaction zone 16, an equilibrium exists between heat input, required reaction energy, and heat losses, where the temperature is approximately constant. A second heat integration zone forms in the area of outlet 4, where the heat of the dissociated stream 9 can be partially recovered and transferred to newly flowing particles of the moving bed 14.
[0070] 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 onto the incoming gas stream 8, and in the region of the outlet 4 from the dissociated stream 9 onto 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 deposits that may occur.
[0071] Fig. 5 shows a third embodiment of reactor 2, in which the solid material 11 is formed as a solid 32 with an open-cell foam structure. The hydrogen sulfide-containing byproduct stream 8 flows through the pores of the open-cell foam structure from the inlet 3 toward the outlet 4. The hydrogen sulfide is dissociated into hydrogen and sulfur by the ohmic heat generated in the solid 32. Instead of an open-cell foam structure, a solid with a preferably three-dimensional lattice structure (not shown) can also be used.
[0072] Otherwise, the statements regarding the first two embodiments apply accordingly.
[0073] 1 chemical plant
[0074] 2 reactors
[0075] 3 Entrance
[0076] 4 Outlet
[0077] 5 Reaction chamber
[0078] 6 reactor shell
[0079] 7 Reactor lining
[0080] 8 By-product stream
[0081] 9 dissociated current
[0082] 10 sulphurous current
[0083] 11 Solid material
[0084] 12 Electrode
[0085] 13 fixed beds
[0086] 14 Travel bed
[0087] 15 first reaction zone
[0088] 16 second reaction zone
[0089] 17 Input material stream
[0090] 18 Hydrofiner
[0091] 19 first separating device
[0092] 20 Product stream
[0093] 21 desulfurized heating gas
[0094] 22 hydrogen sulfide-containing condensate
[0095] 23 Residual current
[0096] 24 first repatriation
[0097] 25 hydrogen-containing gas stream
[0098] 26 discharged gas stream
[0099] 27 second separating device
[0100] 28 second return
[0101] 29 Treatment device
[0102] 30 cooling section
[0103] 31 Conveyor device
[0104] 32 solids
Claims
PATENT CLAIMS 1. Chemical plant for the hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream (17), comprising a hydrofiner (18) for producing a desulfurized product stream (20) and a hydrogen sulfide-containing by-product stream (8) from the feed 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 thatthat the reactor (2) for the thermal dissociation of the hydrogen sulphide comprises an electrically heated reaction chamber (5) and 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).
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 resistively heating 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 consisting of carbon, metals, carbides or nitrides.
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. A process for the hydrodesulfurization of a hydrocarbon- and sulfur-containing feed stream (17), comprising the following process steps Producing a desulfurized product stream (20) and a hydrogen sulfide-containing by-product stream (8) from the feed stream (17) with admixture of a hydrogen-containing gas stream (25) in a hydrofiner (18), Generating a dissociated stream (9) by dissociating hydrogen sulphide contained in the hydrogen sulphide-containing by-product stream (8) into the components hydrogen and sulphur 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).
12. The method according to claim 11, characterized in that the reaction mixture is cooled in a cooling section (30) of the first separation device (19), wherein the cooling section (30) preferably contains a quench.
13. The process according to claim 11 or 12, characterized in that non-dissociated hydrogen sulfide is separated from the dissociated stream (9) or the residual stream (23) in a second separation device (27) and is 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. The method according to any 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.