Apparatus for separating solid-containing and molten salt-containing streams - Patent Application 20070122997
A cyclone and hopper system with heating and vacuum processing effectively separates and purifies carbon products from methane pyrolysis reactors, addressing agglomeration issues and achieving high-purity carbon with reduced energy use.
Patent Information
- Application Number
- JP2025522542
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-01
- Filing Date
- 2023-10-17
- Publication Date
- 2025-11-05
AI Technical Summary
Existing technologies struggle to efficiently separate and purify carbon products from methane pyrolysis reactors due to molten salt impurities, leading to particle agglomeration and reduced product quality, with existing methods being complex and leaving significant impurities in the final carbon product.
A cyclone separator and hopper system with a heater and vacuum pump are used to separate and evaporate molten salts from carbon solids, allowing for high-temperature processing and direct purification of carbon products, minimizing agglomeration and increasing purity.
The system achieves a highly pure carbon product with minimal waste streams by sublimating and evaporating molten salts, resulting in a carbon product with over 99.0% purity and reduced energy consumption compared to conventional methods.
Smart Images
Figure 2025536330000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an apparatus for separating solid-containing and molten salt-containing streams. [Background technology]
[0002] Apparatus for separating solids-containing streams is known in the art. By way of example only, cyclone and hopper combinations have been used for decades to separate solids-containing streams.
[0003] By way of example only, U.S. Patent No. 2,863,821 discloses in Figure 2 the use of a cyclone (64) and hopper (51) in a fluidized coking vessel where a product vapor-solids separator is located internally within the vessel and the temperature of the fluidized bed is maintained by a transfer line burner system. This type of apparatus is not intended to process (solids-containing and) molten salt-containing streams.
[0004] For example, a problem with solids-containing streams coming from methane pyrolysis reactors is that carbon particles from the reactor may contain levels of molten salts that can induce particle agglomeration, leading to blockages in the piping and negatively impacting the quality of the final carbon product.
[0005] Chinese Patent No. 114405827(A) discloses a method for separating carbon materials in molten salt, which includes the following five steps: (1) crushing and pulverizing the mixed product of salt and carbon in a crusher; (2) grinding the crushed and ground salt-carbon mixture in a ball mill; (3) sieving the ground salt-carbon mixture through a porous sieve; 4) placing the sorted salt-carbon mixture on a wind sorting platform and wind sorting at a constant wind speed and a constant sample table height; and (5) collecting the salt-carbon products in the two precipitation zones, respectively.
[0006] The drawback of this method disclosed in Chinese Patent No. 114405827(A) is that it is very complicated.
[0007] A further drawback of the method disclosed in CN Patent No. 114405827(A) is that after separation, about 7 wt% of molten salt impurities still exist in the obtained carbon product, which significantly affects the value of the carbon product. Summary of the Invention [Problem to be solved by the invention]
[0008] It is an object of the present invention to solve, minimize, or at least reduce one or more of the above-mentioned problems associated with handling solids-containing and molten salt-containing streams.
[0009] It is a further object of the present invention to provide an alternative apparatus for separating solid-containing and molten salt-containing streams resulting from a methane pyrolysis reactor.
[0010] It is yet another object of the present invention to provide an apparatus and method for providing a purified carbon product stream by removing molten salt impurities from carbon products, particularly those obtained in methane pyrolysis reactors. [Means for solving the problem]
[0011] One or more of the above or other objects may be achieved in accordance with the present invention by providing an apparatus for separating solids-containing and molten salt-containing streams, the apparatus comprising at least: a cyclone separator having an inlet for the solids-containing and molten salt-containing streams to be separated, a bottom dipleg outlet for the wet solids stream, and a top outlet for the gas stream; a hopper having a top inlet, a top outlet, and a bottom outlet, the top inlet of the hopper being fluidly connected to the bottom dipleg outlet of the cyclone separator; and a heater for heating the wet solids in the hopper, A vacuum pump is connected to an overhead space within the hopper defined by the walls of the hopper and the surface level of the wet solids within the hopper.
[0012] Surprisingly, it has been found in accordance with the present invention that by using an apparatus in accordance with the present invention, molten salts can be removed from a (typically carbon-containing) solids stream by (sublimation and) evaporation in a surprisingly simple manner, resulting in minimal particle agglomeration and a higher purity solids stream exiting the apparatus.
[0013] A further advantage of the apparatus according to the present invention is that during use of the apparatus according to the present invention, the carbon solids product can be purified at high temperatures and typically obtained directly (i.e., without first being cooled) from a preceding methane pyrolysis reactor, resulting in overall greater energy efficiency and the generation of fewer waste streams (such as wastewater) compared to conventional processes where the carbon solids product must first be cooled for subsequent purification, e.g., using water washing or other methods.
[0014] Those skilled in the art will be familiar with cyclone separators, hoppers, vacuum pumps and heaters themselves, and therefore these will not be described in detail herein.
[0015] As described above, the cyclone separator has an inlet for the solids-containing and molten salt-containing streams to be separated, a bottom dipleg outlet for the wet solids stream (which contains some liquid molten salt impurities), and a top outlet for the gas stream. Those skilled in the art will readily appreciate that additional inlets and outlets may be present.
[0016] Preferably, the inlets for the solid-containing and molten salt-containing streams to be separated are connected to the outlet of the methane pyrolysis reactor, in other words, the device according to the invention is preferably arranged after the methane pyrolysis reactor.
[0017] Typically (and preferably), the inlets for the solids-containing and molten salt-containing streams are tangential or involute inlets.
[0018] According to a preferred embodiment of the apparatus according to the invention, the bottom dipleg outlet of the cyclone separator opens into the hopper below the surface level of the wet solids in the hopper.
[0019] Also, as noted above, the hopper includes a top inlet, a top outlet, and a bottom outlet, and the top inlet of the hopper is fluidly connected to the bottom dipleg outlet of the cyclone separator. Again, those skilled in the art will readily appreciate that additional inlets and outlets may be present.
[0020] Preferably, the hopper is located below the cyclone separator.
[0021] As further described above, the apparatus includes a vacuum pump connected to the top outlet of the cyclone separator. In accordance with the present invention, the vacuum pump is connected to an overhead space within the hopper defined by the wall of the hopper and the surface level of the wet solids within the hopper.
[0022] As noted above, the apparatus also includes a heater capable of heating the wet solid in the hopper during use, thereby allowing at least a portion of the molten salt in the wet solid to sublimate and evaporate. Preferably, the heater is capable of heating the wet solid in the hopper to at least 700°C, preferably at least 800°C, more preferably at least 950°C.
[0023] Preferably, the heater comprises an indirect heat exchanger including a heating tube passing through the interior of the hopper.
[0024] According to a preferred embodiment of the present invention, the apparatus further comprises a controller connected to the vacuum pump for maintaining sufficient vacuum in the hopper during use to evaporate the molten salt in the wet solids in the hopper (preferably in the lower part thereof).
[0025] In a further aspect, the present invention provides a process for separating solid-containing and molten salt-containing streams, in particular using an apparatus according to the present invention, said process comprising at least (a) providing a solids-containing and molten salt-containing stream, the solids-containing and molten salt-containing stream comprising at least 1 wt. % liquid molten salt based on the total amount of liquids and solids in the solids-containing and molten salt-containing stream; the solids-containing and molten salt-containing streams comprise at least 50 wt. % carbon solids based on the total amount of liquids and solids in the solids-containing and molten salt-containing streams; (b) feeding the solids-containing and molten salt-containing streams provided in step (a) into a cyclone separator via an inlet; (c) separating the solids-containing and molten salt-containing streams in a cyclone separator, thereby obtaining a wet solids stream and a gas stream; (d) removing a wet solids stream from the cyclone separator via a bottom dipleg outlet and a gas stream via a top outlet; (e) receiving the wet solids stream into a hopper via a top inlet, the top inlet of the hopper being fluidly connected to the bottom dipleg outlet of the cyclone separator; (f) heating the wet solid in the hopper to at least 700°C, thereby sublimating and evaporating at least a portion of the molten salt in the wet solid; (g) removing solids from the hopper through a bottom outlet of the hopper; (h) removing gas from the hopper through the top outlet using a vacuum pump connected to the top outlet of the hopper.
[0026] In step (a) of the process according to the present invention, a solid-containing and molten salt-containing stream is provided. The solid-containing and molten salt-containing stream provided in step (a) is not particularly limited, but is typically a three-phase stream, i.e., containing gas, liquid, and solid. Preferably, the solid-containing and molten salt-containing stream originates from a methane pyrolysis reactor.
[0027] Preferably, the solid-containing and molten salt-containing stream provided in step (a) contains at least 5 wt. %, more preferably at least 10 wt. %, and even more preferably at least 25 wt. % liquid, based on the total amount of liquid and solids in the solid-containing and molten salt-containing stream. Typically, the solid-containing and molten salt-containing stream provided in step (a) contains at most 50 wt. % liquid. Preferably, the liquid is a molten salt. The molten salt is not particularly limited and can be selected from a wide variety of molten salts, such as NaCl, KCl, CaCl, MgCl, NaNO, KNO, Ca(NO), Mg(NO), or mixtures of these salts. Preferably, the molten salt is selected from the group consisting of NaCl, KCl, CaCl, NaNO, KNO, and Ca(NO), more preferably NaCl or KCl. It is particularly preferred that the molten salt has a melting point or melting point range of 500 to 800°C.
[0028] According to the present invention, the solids-containing and molten salt-containing stream provided in step (a) comprises at least 50 wt. %, preferably at least 75 wt. %, more preferably at least 90 wt. % carbon solids based on the total amount of liquids and solids in the solids-containing and molten salt-containing stream.
[0029] Furthermore, it is preferred that the solids-containing and molten salt-containing streams provided in step (a) comprise at most 90 wt. % gas, preferably at most 95 wt. % gas, based on the total (gas, liquid and solids) stream provided in step (a).
[0030] Typically the gas contains more than 50% by volume H2 and less than 50% by volume CH4, preferably more than 75% by volume H2 and less than 25% by volume CH4.
[0031] According to a particularly preferred embodiment of the process according to the invention, the solids-containing and molten salt-containing stream provided in step (a) has a temperature of at least 800° C., preferably at least 850° C. (typically at most 950° C.). As mentioned above, the solids-containing and molten salt-containing stream provided in step (a) is preferably obtained directly (without first cooling) from a preceding methane pyrolysis reactor.
[0032] In step (b) of the process according to the invention, the solids-containing and molten salt-containing streams provided in step (a) are fed to a cyclone separator via an inlet.
[0033] In step (c) of the process according to the invention, the solids-containing and molten salt-containing streams are separated in a cyclone separator, thereby obtaining a wet solids stream and a gas stream. According to the invention, a "wet solids" stream means a solids-containing stream that contains at least 1 wt. % liquid, based on the total amount of liquid and solids in the stream. It should be noted in this regard that "wet" does not refer to the presence of water (but rather to the presence of molten salt).
[0034] In step (d) of the process according to the invention, a wet solids stream is removed from the cyclone separator via the bottom dipleg outlet and a gas stream is removed via the top outlet.
[0035] In step (e) of the process according to the invention, the wet solids stream is received into a hopper via a top inlet, the top inlet of the hopper being fluidly connected with the bottom dipleg outlet of the cyclone separator.
[0036] Preferably, the bottom dipleg outlet of the cyclone separator opens into the hopper below the surface level of the wet solids in the hopper.
[0037] In step (f) of the process according to the invention, the wet solid in the hopper is heated to at least 700° C., thereby allowing (sublimation and) evaporation of at least a portion of the molten salt in the wet solid.
[0038] According to a particularly preferred embodiment of the process according to the invention, in step (f), a vacuum sufficient to evaporate the liquid molten salt in the wet solid in the hopper, preferably at its bottom, is maintained. Preferably, a vacuum of at most 500 Pa, preferably at most 200 Pa (typically more than 50 Pa), is maintained. Preferably, in step (f), the wet solid is heated to at least 800°C, more preferably at least 950°C.
[0039] In step (g) of the process according to the invention, solids are removed from the hopper through its bottom outlet. Typically, the removed solids stream is a carbon solids-enriched stream (containing at least 99.0% by weight of carbon solids). The carbon solids-enriched stream is the desired product of the process and can be used as a carbon material for a variety of applications.
[0040] In step (h) of the process according to the invention, gas is removed from the hopper via the top outlet using a vacuum pump connected to the top outlet of the hopper. Typically, the removed gas contains vaporized (sublimated) molten salt.
[0041] The invention will now be further illustrated by the following non-limiting drawings, in which: For the purposes of this description, the same reference numbers refer to identical or similar components. [Brief explanation of the drawings]
[0042] [Figure 1] 1 shows a schematic representation of an apparatus for separating solid-containing and molten salt-containing streams according to the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0043] The apparatus shown in FIG. 1, generally designated by the reference numeral 1, includes a cyclone separator 2, a hopper 3, a vacuum pump 4 and a heater 5.
[0044] Cyclone separator 2 has an inlet 21 for the solids-containing and molten salts-containing stream 10 to be separated, a bottom dipleg outlet 22 for the wet solids stream, and an overhead outlet 23 for the gas stream. Preferably, solids-containing and molten salts-containing stream 10 originates from a methane pyrolysis reactor (not shown). In such case, inlet 21 of cyclone separator 2 is connected to the outlet of the methane pyrolysis reactor.
[0045] The hopper 3 includes a top inlet 31 , a top outlet 32 , and a bottom outlet 33 , and the top inlet 31 of the hopper 3 is fluidly connected with the bottom dipleg outlet 22 of the cyclone separator 2 .
[0046] In the embodiment of FIG. 1, the bottom dipleg outlet 22 of the cyclone separator 2 opens into the hopper 3 below the surface level 35 of the wet solids 34 therein.
[0047] In the embodiment of FIG. 1, vacuum pump 4 is connected to an overhead space 36 within hopper 3 defined by the walls of hopper 3 and the surface level 35 of the wet solids within hopper 3 .
[0048] The heater 5, in use, is capable of heating the wet solids 34 in the hopper 3 to a temperature preferably of at least 700°C.
[0049] Also shown in FIG. 1 is a controller (6) for maintaining sufficient vacuum within the hopper 3 during use to assist in the evaporation of molten salt contained in the wet solids 34 within the hopper 3.
[0050] During use of the apparatus of Figure 1, a solids-containing and molten salt-containing stream 10 is provided (preferably originating directly from a methane pyrolysis reactor without cooling, as described above) and fed to cyclone separator 2 via inlet 21.
[0051] In cyclone separator 2, the solids-containing and molten salt-containing streams are separated, thereby providing a wet solids stream and a gas stream. The wet solids stream is removed from cyclone separator 2 via bottom dipleg outlet 22, while the gas stream is removed as stream 30 via overhead outlet 23.
[0052] The wet solids stream is received into hopper 3 via hopper top inlet 31 , which is fluidly connected with bottom dipleg outlet 22 of cyclone separator 2 .
[0053] In the hopper 3, the wet solid 34 is heated using a heater 5, thereby allowing for the sublimation and evaporation of at least a portion of the molten salt in the wet solid 34.
[0054] The solids are removed from hopper 3 as stream 20 through its bottom outlet 33, and the gas (containing the (sublimated) vaporized molten salt) is removed from hopper 3 as stream 40 through overhead outlet 32 using vacuum pump 4 connected to overhead outlet 32 of hopper 3.
[0055] Preferably, sufficient vacuum is maintained within hopper 3 to aid in the evaporation of the molten salt in the wet solids 34 within hopper 3 . Example
[0056] The apparatus of Figure 1 was used to demonstrate non-limiting separation of solids-containing and molten salt-containing streams.
[0057] Solid-containing and molten salt-containing gas streams were obtained and analyzed from a 2-inch (50.8 mm) diameter methane pyrolysis molten salt reactor. The pyrolysis temperature used was 950°C and the pressure was 1 bara (100 kPaA). In the examples, a mixture of 50 wt% NaCl and 50 wt% KCl was used as the molten salt.
[0058] The compositions and conditions of the fluid (i.e., gas, liquid, and solid) streams in the various flow lines are shown in Table 1 below (V means vapor, L means liquid, and S means solid). The volumetric flow rate of stream 10 was 1.67 L / min. The composition of stream 10 is shown in Table 1: 24.5 wt.% H2(g); 65.5 wt.% CH4(g); 5.0 wt.% C(s); and 5.0 wt.% molten salt (l).
[0059] The values in Table 1 were calculated using a model generated in commercially available Aspen Plus software. The compositions of gas stream 30 and the purified solid carbon composition were measured experimentally using GC and SEM. The simulation results showed that if inlet stream 10 was 100 g, there would be 5.03 g of solids stream 20, 53.6 g of vapor stream 30, and 41.4 g of vapor stream 40.
[0060] [Table 1]
[0061] Example 2 Carbon product purification by evaporation (and sublimation) was also investigated experimentally. Raw carbon product (containing approximately 75 wt.% NaCl / KCl salts) from a methane pyrolysis reactor was used. The raw carbon was loaded into a crucible under nitrogen purging. A vacuum (100 Pa) was applied to the carbon product at 950 °C.
[0062] The compositional changes of the carbon material before and after evaporation (and sublimation) are shown in Table 2 below. It clearly shows that evaporation (and sublimation) under the indicated operating conditions (100 Pa, 950°C) can effectively remove salt impurities from the carbon product. As a result, a carbon product with a purity of over 99.0 wt% can be obtained.
[0063] [Table 2]
[0064] Consideration As can be seen from the simulations in Figure 1 and Table 1, the process according to the present invention allows for a surprisingly simple and effective way to separate solid-containing and molten salt-containing streams to yield a relatively pure (99.4 wt%) carbon product. The surprising results achieved by the present invention were confirmed in an experimental example (Example 2, Table 2).
[0065] Those skilled in the art will readily appreciate that many modifications may be made without departing from the scope of the present invention. Furthermore, those skilled in the art will readily appreciate that, although the present invention has been described in some instances with reference to particular combinations of features and means, many of these features and means are functionally independent of other features and means provided in each embodiment and may be equally or similarly applied independently in other embodiments.
Claims
1. An apparatus (1) for separating a solid-containing and a molten salt-containing stream (10), said apparatus (1) comprising: a cyclone separator (2) having an inlet (21) for the solids-containing and molten salt-containing streams (10) to be separated, a bottom dipleg outlet (22) for the wet solids stream, and a top outlet (23) for the gas stream; a hopper (3) comprising a top inlet (31), a top outlet (32), and a bottom outlet (33), wherein the top inlet (31) of the hopper (3) is fluidly connected with the bottom dipleg outlet (22) of the cyclone separator (2); and - a heater (5) for heating the wet solids (34) in said hopper (3), An apparatus (1) in which a vacuum pump (4) is connected to an overhead space (36) in the hopper (3) defined by the wall of the hopper and the surface level (35) of the wet solids in the hopper (3).
2. 2. The apparatus (1) of claim 1, wherein the bottom dipleg outlet (22) of the cyclone separator (2) opens into the hopper (3) below the surface level (35) of the wet solids (34) in the hopper (3).
3. 3. The apparatus (1) according to claim 1 or 2, wherein the heater (5) is capable of heating the wet solids (34) in the hopper (3) to at least 700°C, preferably at least 800°C, more preferably at least 950°C.
4. 4. The apparatus (1) of claim 1, further comprising a controller (6) connected to the vacuum pump (4) for maintaining a sufficient vacuum in the hopper (3) during use to evaporate the molten salt in the wet solids (34) in the hopper (3).
5. A process for separating a solid-containing and a molten salt-containing stream (10) using, in particular, an apparatus (1) according to any one of claims 1 to 4, comprising: (a) providing a solids-containing and molten salt-containing stream (10), said solids-containing and molten salt-containing stream (10) comprising at least 1 wt. % liquid molten salt based on the total amount of liquids and solids in said solids-containing and molten salt-containing stream (10); the solids-containing and molten salt-containing streams comprising at least 50 wt. % carbon solids based on the total amount of liquids and solids in the solids-containing and molten salt-containing streams; (b) feeding the solids-containing and molten salt-containing stream (10) provided in step (a) into a cyclone separator (2) via an inlet (21); (c) separating the solids-containing and molten salt-containing streams in the cyclone separator (2), thereby obtaining a wet solids stream and a gas stream; (d) removing the wet solids stream from the cyclone separator (2) via a bottom dipleg outlet (22) and the gas stream via a top outlet (23); (e) receiving the wet solids stream into a hopper (3) through a top inlet (31), the top inlet (31) of the hopper (3) being fluidly connected to the bottom dipleg outlet (22) of the cyclone separator (2); (f) heating the wet solids (34) in the hopper (3) to at least 700°C, thereby evaporating at least a portion of the molten salt in the wet solids (34); (g) removing solids from the hopper (3) through the bottom outlet (33) of the hopper (3); (h) removing gas from the hopper (3) through the top outlet (32) using a vacuum pump (4) connected to the top outlet (32) of the hopper (3).
6. 6. The process of claim 5, wherein the solids-containing and molten salt-containing stream (10) provided in step (a) comprises at least 5 wt. %, preferably at least 10 wt. %, more preferably at least 25 wt. % liquid molten salt, based on the total amount of liquids and solids in the solids-containing and molten salt-containing stream (10).
7. 7. The process according to claim 5 or 6, wherein the solid-containing and molten salt-containing stream (10) provided in step (a) comprises at most 90 wt.%, preferably at most 95 wt.% gas.
8. The process according to any one of claims 5 to 7, wherein the solid-containing and molten salt-containing stream (10) provided in step (a) has a temperature of at least 800°C, preferably at least 850°C.
9. 9. The process of any one of claims 5 to 8, wherein in step (f) a vacuum sufficient to evaporate liquid molten salt in the wet solids (34) is maintained in the hopper (3).
10. A process according to any one of claims 5 to 9, wherein in step (f) the wet solid (34) is heated to at least 800°C, preferably at least 950°C.