Method and device of separating and removing solid carbon from hydrogen generation reactor decomposing methane and / or low co2 discharged hydrocarbon and refining solid carbon

Abstract

To provide a device capable of cooling solid carbon generated in a reactor so as to be easily conveyable, while continuously removing the solid carbon from both of a molten metal and / or a molten salt and a gas stream, maintaining the operation pressure, and restricting the content of methane and H2 adsorbed by a solid to a minimum level.SOLUTION: There are provided the device and the method of continuously separating and removing a solid residue generated by the conversion of a hydrocarbon to carbon and hydrogen, from a uniform phase of a different density not dissolving the solid residue contained in a decomposition reactor and refining the solid residue, with the separation of the solid carbon occurring in the following two instances. A first separation occurs between the carbon-containing reaction product and a molten bath in the reactor, and subsequently a second separation occurs between the gas and the carbon generated in the separation system (1) of the solid phase from the gas phase outside the reactor. The separation system (1) includes refining of the carbon.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and a method for separating an insoluble solid residue from a homogeneous phase of different density contained within the same reactor, and for continuously removing and purifying it from a reactor (R).

[0002] The field of application is the separation, removal of solid residues from reactor loops, i.e. cracking reactors for converting hydrocarbons into hydrogen and carbon, as well as the purification of solid residues produced inside reactors in which the above reactions take place in a molten bath consisting of metals and / or molten salts. [Background technology]

[0003] It is known that the conversion of natural gas or other hydrocarbons to H2 and solid carbon could be a viable alternative to the electrolysis of water using renewable electricity due to the high production costs of electrolysis. These costs are primarily due to the need to break OH bonds, which are particularly strong compared to C-H bonds.

[0004] From this point of view, the decomposition of natural gas in a molten medium, such as molten metal and / or salt, with or without the presence of a catalyst, is an option and a very interesting alternative to produce H2 without CO2 emissions. As is known, the decomposition reaction of methane (1) is fully endothermic, as shown in the following reaction: CH 4(g) =C (s) +2H 2(g) ΔH=74 kJ / mol(1)

[0005] However, the cracking of methane is only one example of the simplest case among a wide range of saturated hydrocarbons that can be cleaved by breaking a C-H bond. C n H 2n+n =nC (s) +(n+1)H2(2)

[0006] The removal of solid carbon from inside the reactor is one of the main difficulties in using CH4 decomposition technology in molten metal and / or molten salt reactors, especially when operating conditions are achieved where the reactor operates at pressures of 10-20 barg, also taking into account the fact that solid carbon has a tendency to adsorb gases, especially hydrocarbons, albeit in trace amounts.

[0007] The importance of this removal is determined by the fact that at reactor temperatures, i.e., 800-1200 °C, 70-80 wt. % of the feed leaves the reactor in the form of solid coal with a relatively dusty and poorly compacted structure (see Figure 4).

[0008] Below are some application examples for removing solid coal from a cracking reactor in the presence of a melting medium.

[0009] To facilitate removal of coal from a molten bath, WO 2019 / 099795, entitled "Simultaneous reactions and separation of chemicals," discloses the use of molten liquid salt above the bath where the solid coal is concentrated.

[0010] This layer then leaves the reactor and enters a separate chamber where the coal is mechanically separated and the molten salt used to extract the solids is returned to the reactor.

[0011] In this patent, the coal collection zone is in the annulus of the reactor due to the density difference between the central zone where the charge is injected and bubbled, and the lateral torus where the molten metal and salt reside. There is no mention in the text of this patent of the operating pressure of the reactor.

[0012] Patent document 2, WO 2020 / 046583, “Systems and processes for molten media pyrolysis”, also relates to the “reactor loop” concept, but in which “seed particles” are introduced to facilitate separation of the solid fraction with the aim of increasing the average size of the coal particles, and alternative or synergistic operating methods are presented, which are adapted to increase the residence time and thus the particle size of the coal particles.

[0013] On the other hand, no specific instructions are given for the solids extraction method, except for having the option of installing a "screw feeder".

[0014] In patent 3, U.S. Pat. No. 10,851,307, “System and method for pyrolysis using a liquid metal catalyst,” the morphological characteristics of solid coal are described in relation to the type of catalyst used, and coal separation is carried out in a separate vessel, although a scraper or agitator as well as gas jets can be included in the main reactor to remove solids.

[0015] However, the claims do not mention how solids are removed.

[0016] US Patent Application Publication No. 2004 / 0253168, entitled "System and method for hydrocarbon processing", relates to the production of nanostructured coal and hydrogen in a "spouted bed" type reactor, where the removal of coal is achieved by a sleeve filter which processes the gas / solid mixture and recovers the solids, the latter being removed when the system is shut down, hence its discontinuous operation.

[0017] The work in Non-Patent Document 1 provides a reactor containing liquid metal, subsequent steps of separating carbon from the liquid metal, separating carbon from gas, separating hydrogen from gas, and then recycling the unreacted feedstock (methane) to the reactor, but does not specifically show how such separation steps are performed.

[0018] Thus, as can be seen from the cited literature, the removal of solid coal is a key step in the natural gas cracking process. Such a step strictly depends on a number of factors, which can be mentioned as follows: the high amount of solids to be removed, the adsorption of gases (thus implying a continuous process), the fact that the reactor operates at high pressure, typically 10-20 barg, and finally, the morphological characteristics of the coal to be removed.

[0019] Indeed, in this type of process, the average carbon size can range from tens of microns (see FIG. 4) to hundreds of microns.

[0020] Moreover, the amount and characteristics of such coal make such removal from cracking reactors particularly difficult, especially in commercial situations that require continuous operation, thus avoiding the need to stop production to remove solids.

[0021] Patent document 5, U.S. Pat. No. 6,110,239, describes a process for simultaneously, separately and continuously producing high purity high pressure hydrogen-rich and high pressure carbon monoxide-rich gas streams using a molten metal gasifier containing at least two zones, thus avoiding the need to separate or compress the gases in downstream equipment.

[0022] Essentially, hydrocarbons are split open in a first chamber by separating hydrogen from the molten mass that the coal is trapped in, and then the molten mass is sent to a second zone where oxygen is bubbled through to promote the formation of carbon monoxide.

[0023] Alternatively, US Patent Application Publication No. 2022 / 119259 describes a method for pyrolyzing hydrocarbons in molten metal to produce hydrogen gas and carbon, with the carbon resulting from pyrolysis being separated from the molten metal using a liquid salt that is immiscible with the molten metal. The introduction of the molten salt therefore facilitates both the separation from the molten bath and the isolation of the carbon produced. [Prior art documents] [Patent documents]

[0024] [Patent Document 1] International Publication No. 2019 / 099795 [Patent Document 2] International Publication No. 2020 / 046583 [Patent Document 3] U.S. Patent No. 10,851,307 [Patent Document 4] US Patent Application Publication No. 2004 / 0253168 [Patent Document 5] U.S. Patent No. 6,110,239 [Patent Document 6] US Patent Application Publication No. 2022 / 119259 [Non-patent literature]

[0025] [Non-Patent Document 1] Abanades et al. “Development of methane decarbonization based on liquid metal technology for CO2-free production of hydrogen”, Int.J.Energia idrogeno 2016,41,8150~8167 Summary of the Invention [Problem to be solved by the invention]

[0026] The objective of the present invention is to overcome the limitations of the background art and provide an apparatus in which solid coal produced in a reactor can be continuously removed from both the molten metal and / or salt and the gas stream while being cooled for easy transport, maintaining the operating pressure and minimizing the content of methane and H2 adsorbed on the solids. [Means for solving the problem]

[0027] The proposed solution is to take advantage of the insolubility of the solids with homogeneous phases of different density present in the reactor, promoting stratification and accumulation of said solids inside the reactor, and thus using the gas stream emitted by the reactor as a carrier to transport the same solids towards an external processing circuit, where the gas is separated from the solids, the retained fraction is desorbed and the solids are continuously removed. [Brief description of the drawings]

[0028] A better understanding of the invention will be achieved from the following detailed description and with reference to the accompanying drawings which show preferred embodiments by way of non-limiting example.

[0029] [Figure 1] FIG. 1 is a schematic diagram of how the separation system can be seen outside the reactor. [Diagram 2] Figure 2A) shows a plan section of the reactor R according to the invention. Figure 2B) shows details of the barrier 200 and the weir 201 present inside the reactor R. Figure 2C) shows two vertical sections in two different planes of the reactor R according to the invention. Figure 2D) shows two vertical sections in two different planes of the reactor R according to the invention. [Figure 3A] FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 3B] FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 3C] FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 3D]FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 3E] FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 3F] FIG. 4 illustrates the steps involved in a discharge sequence according to the present invention. [Figure 4] Photographs of some solid coal obtained at temperatures of about 1000°C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] With reference to the accompanying drawing, reactor R is a cracking reactor for converting hydrocarbons into hydrogen (gas) and carbon (solid).

[0031] In the preferred embodiment described, said reactor R is a recirculating or loop reactor in which there is a medium consisting of a bath of molten metal and / or molten salt in the presence or absence of a catalyst in which the solid carbon produced during the reaction is insoluble.

[0032] According to the invention, the separation of solid carbon occurs at two instants: A first separation takes place in the reactor between the carbon-containing reaction products and the molten bath. A second separation then takes place outside the reactor between the carbon and the produced gases.

[0033] While the first separation between the reaction products and the molten bath occurs continuously in the reactor, the second separation between the various reaction products occurs discontinuously, taking into account the tendency of carbon to absorb some of the gases produced.

[0034] To overcome these problems, systems have been developed that allow continuous operation and removal of purified carbon in reactor R, optimize the various separation steps, and minimize the adsorption of gases in the solid carbon.

[0035] According to the present invention, the carbon separation, removal and purification system 1 includes the following elements: at least one reactor R equipped with a barrier 200 and with means for introducing hydrocarbons into the reactor; at least one outlet pipe 10 for connecting the purification system 1 to said reactor R; The purification system 1 also includes: at least one primary separator 20; at least one collection chamber 30 for solid carbon from the primary separator 20; at least one intermediate transfer tank 40 provided with a vent valve, i.e. MP vent valve 41, connected to the medium pressure circuit; · at least one final storage tank 50 provided with a vent valve, i.e. BP vent valve 51, connected to the low pressure circuit, a second atmospheric vent valve, i.e. ATM vent valve 52 and a bottom valve 53 for discharging the coal; at least one primary valve 60 arranged between the collection chamber 30 and the intermediate tank 40 for transferring carbon from said collection chamber to the intermediate tank; · at least one secondary valve 70 arranged between the intermediate tank 40 and the storage tank 50 for transferring carbon from the intermediate tank to the storage tank; ·Control and automation system for opening valves by PLC.

[0036] Essentially, the invention involves a cracking reaction in which hydrocarbons introduced into a reactor are converted to H2 and carbon, followed by a separation in the reactor between the molten mass forming a molten bath and the gas and solid fractions.

[0037] A stream consisting of gas and solids is then removed from the reactor.

[0038] This removal from the reactor is followed by a coal refining step, i.e. separation of gases from solids to avoid adsorption of the gases inside the produced coal. Reactor R

[0039] As described above, the hydrocarbon cracking reaction takes place in a recirculating reactor R in a molten medium, such as molten metal and / or molten salt, with or without a catalyst.

[0040] According to the invention, the reactor R comprises the following elements: A shell 100, optionally internally coated with a refractory material 101, from which at least one outlet nozzle 102 is provided to facilitate the release of the gas / solids stream produced within said reactor. A barrier 200 of hollow cylindrical shape made of refractory material, coaxial with the reactor shell 100. Said barrier comprises at least one weir 201 at the top and at least one opening at the bottom to allow both the installation of said barrier 200 in the hydrocarbon distribution zone and the passage of molten metal from the annular zone to the inner zone. At least one distributor 300 located at the bottom of the reactor R for injecting hydrocarbons into the reactor. An impeller 400, or scraper, operated by a shaft 401 driven by a motor located outside the reactor.

[0041] The cylindrical volume inside the barrier 200 is the reaction zone, and the volume between the shell 100 of the reactor R and the outer surface of the barrier 200 is the quiescent zone.

[0042] In reality, the quiet zone is an annular portion disposed between the shell 100 and the barrier 200 .

[0043] Following the introduction of hydrocarbons into the reactor and the cracking reaction, a mass is obtained in the reaction zone consisting of a gas phase (reaction products and unreacted hydrocarbons), a solid carbon phase contained in a molten bath.

[0044] Thus, the molten bath has two different densities within the reactor: in the reaction zone, the molten bath has a lower density due to the bubbling therein of the hydrocarbons introduced into the reactor through distributor 300, while in the quiescent annular zone, the molten bath has a higher density due to both separation of products from the molten mass and localized cooling due to distance from the reaction zone.

[0045] This density difference causes a stirring movement of the molten mass between the reaction zone and the quiescent zone.

[0046] According to the invention, the passage of the molten metal from the reaction zone to the calm zone occurs due to the density difference existing in the two zones and through one or more special openings or weirs 201 present in said barrier 200, which makes it possible to collect by dragging most of the solid carbon produced in the annular zone.

[0047] The insolubility of the carbon produced during the reaction in the liquid metal phase causes the formation of a layer of the same on the free surface of the molten bath in the quiet annular zone, while the gases produced spontaneously separate from the molten mass and accumulate at the top of the reactor.

[0048] Coal migration occurs primarily due to the inherent geometry of the reactor, where density differences between the central reaction zone and the lateral quiescent zones promote recirculation of the molten medium, creating level differences that push the coal from the center toward the periphery through one or more cavities located in close proximity to one or more discharge zones.

[0049] Furthermore, the presence of a scraper 400, driven for example by a shaft 401 driven by an external magnetically coupled motor, can improve the movement of solids accumulated on the free surface from the central zone to the annular zone.

[0050] In the described, non-limiting preferred embodiment, the scraper 400 has a diameter larger than that of the barrier and smaller than that of the shell, making it possible to avoid the accumulation of coal on the barrier itself.

[0051] After being transported from the molten bath outside the central reaction zone over the barrier 200 by the weir 201, the coal is moved by flotation from the same molten bath from the discharge point of the weir 201 towards the exit nozzle (102) from the reactor.

[0052] In the illustrated non-limiting preferred embodiment, the reactor exit nozzle (102) is angularly offset relative to the discharge point of the weir 201.

[0053] This can promote further separation of reaction products from the molten bath during their passage from the discharge point of the weir 201 towards the exit nozzle 102 . Outlet pipe 10

[0054] Said annular zone is connected to at least one outlet pipe 10 to allow the discharge of solids by means of the emission of gas from the cracking reactor, the upper level of which is located above the free surface of the molten metal under all operating conditions.

[0055] In effect, the carbon produced and accumulated in the quiet annular zone is carried away by the gaseous stream of hydrogen produced in the reactor, which then acts as a carrier for its removal.

[0056] The outlet pipe 10 can be made either of refractory or metallic material, depending on the temperature reached by the chamber.

[0057] In a preferred, but non-limiting embodiment, said pipe 10 is cooled so as to reduce the temperature of the stream consisting of gas and solids from the value existing in the reactor, which is equal to about 1000-1200°C, to a value equal to about 800-900°C. Primary separator 20

[0058] Downstream of the outlet pipe 10 there is at least one primary separator 20 .

[0059] In the described, non-limiting preferred embodiment, the primary separator 20 is a cyclone that operates under the same pressure conditions as the reactor and allows for a first separation between the gases.

[0060] Optionally, the primary separator 20 may be provided with a cooling system.

[0061] The upper part of the primary separator 20 from which flows the gas separated from the solids, consisting mainly of hydrogen and methane, is connected to a manifold which leads said gas to a subsequent purification unit, after heat recovery with the residual heat of the hydrocarbon stream entering the reactor.

[0062] The gas stream consisting of hydrogen and methane leaving the primary separator 20 can optionally be sent to an additional dedusting step, for example in a bag filter type or other suitable device, before final purification processing.

[0063] The purification unit may be of the Pressure Swing Adsorption (PSA) or membrane or heat recovery type.

[0064] Solids recovered from the gas stream accumulate at the bottom of the primary separator 20 .

[0065] The cyclone separator is designed for adequate pressure drop to allow coal dust to coalesce, facilitating the subsequent step of extracting solids from its bottom.

[0066] In order to avoid the phenomena of dust agglomeration and blockage of the outlet located at the bottom of the separator, the primary separator 20 is preferably, but not necessarily, equipped with a suitable vibrator 21 at its bottom.

[0067] Further optionally, the bottom of the primary separator may be provided with a system for cooling the solids with nitrogen or other medium.

[0068] The pressure in the primary separator 20 is controlled with a crude hydrogen discharge manifold after purifying the same in an appropriate purification unit.

[0069] The pressure in the crude hydrogen manifold is set at 10-20 barg, with a pressure drop to the cracking reactor of 1-5 bar.

[0070] Additionally, overpressure control with gas venting in the torch vent network is included above the cracking reactor and before the purification unit.

[0071] Depending on the gas stream being treated, it is possible to include a set of primary separators 20 operating in parallel. Collection Chamber 30

[0072] The lower part of the primary separator 20, where the solids separated from the gas accumulate, is connected to a solid carbon collection chamber 30, which is equipped with a cooling system 31 making it possible to cool both the solid coal and any entrained solids of the solid / gas mixture to a temperature between 500°C and 600°C.

[0073] Passage of solids from the bottom of the primary separator 10 to the collection chamber 30 occurs by gravity. Primary Valve 60

[0074] Included below the collection chamber 30 is an automatic or primary valve 60 that is adapted to allow the controlled passage of coal from the collection chamber 30 towards a zone disposed downstream of the valve.

[0075] The opening and closing of the valve is controlled by a PLC so that the valve only opens if there is a sufficient amount of solid carbon in the collection chamber 30. Furthermore, an end-of-stroke system is placed on this valve, making it completely safe to open and close it. Intermediate Tank 40

[0076] The opening of the primary valve 60 allows communication between the upstream part of the valve, consisting of the primary separator 20 and the collection chamber 30, which has a higher pressure substantially equal to the reactor pressure (as long as there is no pressure loss), and the downstream part of the valve, consisting of the intermediate tank 40, which has a lower pressure. Thus, a movement of coal from the upstream zone towards the downstream zone occurs due to the pressure gradient created.

[0077] In a preferred but non-limiting embodiment, the intermediate tank 40 is of small volume to minimize pressure disturbances inside the collection chamber 30 and thus the primary separator 20 after the primary valve 60 opens.

[0078] According to the invention, the intermediate transfer tank 40 is provided with a valve 41 for connection to the medium pressure (MP) circuit and pressure / vent control to allow depressurization of the tank itself after carbon has been discharged from the collection chamber 30 towards the intermediate tank 40.

[0079] The MP decompression pressure is set to about 4-8 bar to desorb methane-based gas at a pressure value that allows it to be fed to the second stage of the compressor and to recycle the gas in the reactor.

[0080] Furthermore, in the preferred embodiment described, said intermediate tank 40 is provided with a coal cooling system 42 with nitrogen and / or other refrigerants. Secondary Valve 70

[0081] Below the intermediate tank 40, a second automatic valve, i.e. secondary valve 70, is provided for the controlled discharge of the coal accumulated in the intermediate tank 40 towards a downstream zone of said second valve. Storage tank 50

[0082] Coal from the intermediate tank 40 is directed to the storage tank 50 by the controlled opening of a secondary valve 70 .

[0083] According to the invention, the storage tank 50 is provided with a vent valve connected to the low pressure circuit, i.e. BP vent valve 51, a second atmospheric vent valve, i.e. ATM vent valve 52 and a bottom valve 53 for discharging the coal.

[0084] The BP vent pressure of this tank is 0.1-1 barg, more preferably 0.1-0.2 barg, to allow the desorbed gas to mix with the purge gas from the PSA and both to be recycled to the reactor.

[0085] Final venting of carbon from the storage tank 50 occurs after further depressurization to atmospheric pressure by the ATM vent valve 52. In this case, the gas is no longer recycled as in the previous depressurization but is sent to the vent (VENT).

[0086] Optionally, the final storage tank 50 may be equipped with a solid-state cooling system so that subsequent discharge can occur at a temperature close to that of the environment.

[0087] A particular feature of the invention is that the elements forming the separation system 1 operate according to a sequential valve opening mode allowing a progressive discharge of carbon towards the storage tank 50 .

[0088] In the described non-limiting preferred embodiment, the continuous opening system comprises cyclically performing the following six steps as shown in the table below, the acronyms of which are given below: I = cycle start (for each single step) F = End of cycle (at each step) A = valve open -=valve closed

[0089] Once step 6 is complete, the cycle repeats, starting again from step 1.

[0090] In essence, the gradual opening of the valve allows the pressure to be gradually reduced from the pressure value present in the reactor to that of atmospheric pressure, which involves the separation of the carbon from the gaseous matrix and transporting it outside the reactor, and also makes it possible to manipulate the desorption of gases that may be held in the same carbon. JPEG2024008911000002.jpg110162

[0091] As shown, each step includes a cycle start marked by the opening of one or more appropriate valves, and a cycle end marked by the closing of all valves. In particular, each cycle end step determines a dwell time during which all valves are closed at the end of each step to allow pressure equalization in equipment upstream and downstream of the valves.

[0092] Detailed description of the individual purification steps Step 1 At the beginning of step 1, the primary valve 60, located between the collection chamber 30 and the intermediate transfer tank 40, is opened. In this state, the secondary valve 70, located between the intermediate transfer tank 40 and the storage tank 50, is closed.

[0093] In the primary separator 20, the coal entrained by the gas is separated by gravity from the gaseous matrix that entrains it and is deposited in the collection chamber 30. Furthermore, the opening of the primary valve 60 creates a pressure gradient between the primary separator 20 and the intermediate tank 40, promoting further separation between the solids and the gas.

[0094] At the end of step 1, with the intermediate tank 40 at the same pressure as the primary separator 20, the primary valve 60 closes.

[0095] In this condition, there is no pressure difference between the primary separator 20 and the intermediate tank 40. Assuming having multiple primary separators 10, the control logic defines a sequence of opening / closing of the primary valves 60 and secondary valves 70.

[0096] Thus, at the end of step 1, the coal-filled intermediate tank 40 is substantially insulated since the MP vent valve 41 is also closed.

[0097] Step 2 The start of step 2 involves opening the MP vent valve 41 of the intermediate tank 40 .

[0098] This causes the intermediate tank 40 to have the same pressure as the medium pressure line.

[0099] In the described non-limiting preferred embodiment, the medium pressure is 4 to 8 barg.

[0100] The coal therefore desorbs some of the previously held gas and is therefore discharged from the intermediate tank 40 as a result of the pressure drop.

[0101] At the end of step 2, ie after reduced pressure has been achieved, the MP vent valve 41 is closed.

[0102] Optionally, the intermediate tank 40 is provided with a cooling system 42 adapted to reduce the temperature of the solids to a value close to that of the environment.

[0103] Step 3 The start of step 3 involves opening the secondary valve 70 located between the intermediate tank 40 and the storage tank 50 .

[0104] The pressure differential between the two tanks allows for the transfer of solids from the medium pressure intermediate tank 40 to the low pressure storage tank 50.

[0105] Step 3 ends with the closure of the secondary valve 70. The intermediate tank 40 is now again insulated, but is empty as the coal has been transferred to the final storage tank 50.

[0106] Step 4 In step 4, both the MP vent valve 41, which returns the intermediate tank 40 to medium pressure, and the BP vent valve 51 installed in the storage tank 50 are opened.

[0107] In particular, the opening of the BP vent valve 51 allows the same pressure value to be reached as in the low pressure line.

[0108] In the described non-limiting preferred embodiment, the low pressure value is 0.2 to 0.1 barg.

[0109] The coal thus desorbs any gas that may still be retained and is then discharged from the storage tank 50 by the pressure differential.

[0110] Step 5 The start of step 5 involves opening the ATM vent valve 52 to allow further desorption of gas still retained in the coal.

[0111] The gas thus desorbed is no longer recycled as occurred in the previous step, but is sent to a vent.

[0112] This brings the tank 50 to atmospheric pressure.

[0113] Step 6 Step 6 involves opening the bottom valve 53 to drain the coal outside until the storage tank 50 is empty.

[0114] Once this step is completed, all valves are closed and the cycle repeats starting from step 1.

[0115] Advantageously, the described solution makes it possible to continuously separate the reaction products from the molten bath and remove them from inside the reactor, and also makes it possible to homogenize the separation between the gas obtained from the decomposition reaction and the coal.

[0116] In fact, the discharge of the stream consisting of gas and solids occurs continuously, similar to the operation of the reactor, but the separation of the solid coal from the gas occurs discontinuously, utilizing both the gas stream as the main motor carrier to transport the solids from the reactor towards the separation system and thus to remove them, and the pressure gradient that exists between the reactor R and the removal system 1 for the desorption of the gas retained on the solids themselves.

[0117] The discontinuous discharge of the coal is thus effected in several steps, each of which is discontinuous, and the discontinuities of every single operation are coordinated in a continuous process through the successive opening of valves. Thus, the equipment placed upstream of each valve acts as a buffer for the equipment placed downstream of the same valve, precisely coordinating the entire separation cycle.

Claims

1. An apparatus for continuously separating, removing, and purifying solid residues resulting from the conversion of hydrocarbons to carbon and hydrogen from a homogeneous phase having different densities contained in a decomposition reactor in which the solid residues do not dissolve, wherein the apparatus comprises: - A reactor (R) comprising a shell (100) provided with at least one outlet nozzle (102) to facilitate the discharge of a gas / solid flow generated in the reactor, and a hollow cylindrical barrier (200) made of refractory material coaxial with the shell (100) of the reactor and adapted to divide the volume of the reactor into a quiescent zone and a reaction zone, wherein the barrier comprises at least one weir (201) at the top and at least one opening at the bottom to allow the homogeneous phase having different densities to pass from the annular zone to the inner zone, - At least one distributor (300) located at the bottom of the reactor (R) for injecting hydrocarbons into the reactor, - An impeller (400) or scraper operated by a shaft (401) driven by a motor located outside the reactor, The system (1) for separating the solid phase from the gas phase includes an outlet pipe (10) for connecting the reactor (R), System (1) - At least one primary separator (20) and - At least one collection chamber (30) for solid carbon from the primary separator (20), - At least one intermediate transfer tank (40) is provided with a vent valve connected to the intermediate pressure circuit, i.e., an MP vent valve (41), - At least one final storage tank (50) equipped with a vent valve connected to a low-pressure circuit, i.e., a BP vent valve (51), a second atmospheric vent valve, i.e., an ATM vent valve (52), and a bottom valve (53) for discharging coal, - At least one primary valve (60) is positioned between the collection chamber (30) and the intermediate tank (40) for transferring carbon from the collection chamber to the intermediate tank, - At least one secondary valve (70) is positioned between the intermediate tank (40) and the storage tank (50) for transferring carbon from the intermediate tank to the storage tank, A device comprising a control and automation system for opening the valve by means of a PLC.

2. The apparatus according to claim 1, characterized in that the homogeneous phase is a molten metal and / or a molten salt bath.

3. The apparatus according to claim 2, characterized in that the homogeneous phase contains a catalyst.

4. The apparatus according to claim 1, characterized in that the molten bath has a lower density in the reaction zone, and the lower density is induced by bubbling of the reactants introduced into the reactor by the distributor (300) and by bubbling of the reaction products, and has a higher density in the annular zone due to both the separation of the reaction products from the molten mass and the local cooling of the molten bath due to the distance from the reaction zone.

5. The apparatus according to claim 1, characterized in that the transfer of the molten metal and / or molten salt from the reaction zone to the quiescent zone occurs through one or more special openings present in the barrier (200), due to a density difference between the two zones, the density difference enabling the formation and collection of a layer of solid carbon on the free surface of the molten bath in the quiescent annular zone, the solid carbon being produced by the reaction and insoluble in the molten bath.

6. The apparatus according to claim 5, characterized in that the scraper (400) improves the movement of the solid accumulated on the free surface from the central zone to the annular zone, thereby preventing the accumulation of coal above the weir.

7. The apparatus according to claim 1, characterized in that the outlet nozzle from the reactor (102) is angularly offset with respect to the discharge point of the weir (201) so as to enable the separation of the reaction product from the molten bath during movement.

8. The apparatus according to claim 1, characterized in that the shell (100) is provided with a fire-resistant coating (101).

9. The apparatus according to claim 1, characterized in that the motor that drives the shaft (401) connected to the impeller (400) is of the magnetic coupling type.

10. The apparatus according to claim 1, characterized in that the annular zone of the reactor (R) is connected to the outlet pipe (10) to discharge a flow consisting of gas and solid generated inside the reactor.

11. The apparatus according to claim 10, characterized in that the outlet pipe (10) is made of a fire-resistant material.

12. The apparatus according to claim 10, characterized in that the outlet pipe (10) is made of a metal material.

13. The apparatus according to claim 10, further comprising a cooling system for reducing the temperature of the gas and solid flow from a value equal to the value present inside the reactor, approximately 1000 to 1200°C, to a value equal to approximately 800 to 900°C.

14. The apparatus according to claim 1, wherein the outlet pipe (10) is connected to the primary separator (20), the primary separator (20) is a cyclone separator from which gas and solid flows are separated and a crude gas consisting mainly of crude hydrogen and methane is discharged from the top of the primary separator, the solid is stacked at the bottom of the separator, and the solid contains a certain amount of absorbed hydrocarbon gas.

15. The apparatus according to claim 14, characterized in that a vibrator (21) can be further provided at the bottom of the primary separator (20) to prevent dust aggregation and solid outlet blockage.

16. The apparatus according to claim 14, characterized in that the primary separator may further include a cooling system.

17. The apparatus according to claim 1, characterized in that the bottom of the primary separator (20) is connected to a collection chamber (30) provided with a cooling system (31), and the passage of the solid from the bottom of the primary separator (20) to the collection chamber (30) occurs by gravity.

18. The apparatus according to claim 1, characterized in that the collection chamber (30) is connected to an intermediate tank (40) by an automatic primary valve (60), and the valve adjusts the passage of the solid from the upstream zone with higher pressure to the downstream zone with lower pressure.

19. The apparatus according to claim 18, wherein the intermediate tank (40) is equipped with an automatic MP vent valve (41) connected to an intermediate pressure line, and the valve is capable of reducing the pressure of the intermediate tank (40), and thus enabling the removal of the solid-holding gas.

20. The apparatus according to claim 19, characterized in that the pressure of the intermediate pressure line is preferably 4 to 8 barg.

21. The apparatus according to claim 18, characterized in that the intermediate tank (40) is equipped with a coal cooling system (42).

22. The apparatus according to claim 1, characterized in that the intermediate tank (40) is connected to the final coal storage tank (50) by an automatic secondary valve (70), and the valve adjusts the passage of the solid from the higher-pressure upstream zone to the lower-pressure downstream zone.

23. The apparatus according to claim 22, characterized in that the storage tank comprises a BP vent valve (51) connected to a low-pressure line to allow depressurization of the storage tank (50) and thus desorption of solid-holding gas, a second ATM vent valve (52), and a bottom valve (53) for discharging coal.

24. The apparatus according to claim 1, characterized in that both the gas desorbed by the MP vent valve (41) and the gas desorbed by the BP vent valve (51) can be recycled to the reactor (R) after compression.

25. A method for continuously separating, removing, and purifying the solid residue resulting from the conversion of hydrocarbons to carbon and hydrogen from a homogeneous phase having different densities contained in a decomposition reactor R in which the solid residue does not dissolve, using the apparatus described in claim 1, comprising the following steps: - Decomposition reaction in the reactor R, resulting in the release of carbon and H ２ Generation; - Separation of the solid fraction obtained from the reaction due to the insolubility of the solid in the molten bath; - Separation of gas from the solid mass due to density difference; - Removal of the solid phase from the reactor by external transfer using the gas flow coming out of the reactor R; - Purification of the carbon contained in the gaseous and solid stream by stepwise pressure reduction and stepwise cooling, A method characterized by the following being performed continuously.

26. The method according to claim 25, characterized in that the movement of the coal from the discharge point of the weir (201) to the outlet nozzle (102) is caused by dragging using the movement of the molten bath.

27. The method according to claim 25 or 26, characterized in that the purification step is carried out by sequentially opening the valve, comprising the following steps: Step 1: Open the primary valve (60) o-Cycle start: Open the primary valve (60), close all remaining valves; Cycle complete: Close all valves; Step 2: o-Cycle start: Open MP vent valve (41), close all remaining valves; Cycle complete: Close all valves; Step Phase 3: o-Cycle start: Open secondary valve (70), close all remaining valves; Cycle complete: Close all valves; Step 4: oCycle start: Open MP vent valve (41) and BP vent valve (51), close all remaining valves; Cycle complete: Close all valves; Step 5: o-Cycle start: Open ATM vent valve (52), close all remaining valves; Cycle complete: Close all valves; Step 6: o-Cycle start: Open bottom valve (53), close all remaining valves; Cycle complete: Close all valves; A method in which, at the end of step 6, the entire sequence restarts from step 1.

28. The method according to claim 25, characterized in that the pressure of the low-pressure line is 0.1 to 1 bar, more preferably 0.1 to 0.2 bar.

29. The method according to claim 25, characterized in that the crude gas discharged from the primary separator (20) is sent to a purification unit that enables the separation of the generated hydrogen from any recyclable gaseous hydrocarbon components in the reactor (R) after compression.

30. The method according to claim 25, characterized in that the crude gas flowing into the purification unit is pretreated in a further separation step for the purpose of removing solid particles still present in the gas stream.

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