Green steam industrial steam generator process and system

Abstract

A steam generation system includes a silo, a heater, a material transfer system, and a heat exchanger. The silo is configured to receive granular material in its upper portion. The heater is arranged in or within the upper portion of the silo to heat the granular material received in the silo. The material transfer system is arranged to remove granular material exiting from the bottom of the silo. The heat exchanger is located in the lower portion of the silo and is arranged to contact the granular material flowing downwards into the silo. Electricity for operating the heater can be generated using renewable energy sources (e.g., solar or wind power).

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 358,076, filed on July 1, 2022. The entirety of U.S. Provisional Patent Application No. 63 / 358,076, filed on July 1, 2022, is incorporated herein by reference.

[0002] The following is about the green energy field, steam generation field and related fields. Prior Art

[0003] none Summary of the Invention

[0004] In some illustrative embodiments disclosed herein as non-limiting examples, a steam generation system includes a silo, a heater, a material transfer system, and a heat exchanger. The silo is configured to receive granular material in an upper portion of the silo. The heater is disposed at or within the upper portion of the silo to heat the granular material received in the silo. The material transfer system is configured to remove granular material from the bottom of the silo. The heat exchanger is disposed in the lower portion of the silo and is arranged to contact the granular material flowing downward into the interior of the silo.

[0005] In some illustrative embodiments disclosed herein as non-limiting examples, a steam generation method is disclosed that is performed in conjunction with the steam generation system of the immediately preceding paragraph. The steam generation method includes: delivering granular material to an upper portion of a silo of the steam generation system; delivering electricity to operate a heater of the steam generation system; and flowing a heat transfer fluid through a heat exchanger of the steam generation system. In some embodiments, the delivery of granular material, the delivery of electricity, and the flow of the heat transfer fluid are performed simultaneously. In some embodiments, the delivery of electricity to operate the heater includes generating electricity from solar or wind power.

[0006] In some illustrative embodiments disclosed herein as non-limiting examples, a steam generation system includes a silo, a heater, a heat exchanger, a material transfer system, and a storage silo. The silo is configured to receive granular material in an upper portion of the silo. The heater is arranged to heat the received granular material to produce heated granular material. The heat exchanger is disposed in the lower portion of the silo and is arranged to extract heat from the heated granular material flowing downward into the silo to produce cooled granular material. The material transfer system is arranged to remove the cooled granular material from the bottom of the silo. The storage silo is connected to store the cooled granular material removed by the material transfer system and to transfer the granular material from the storage silo to the upper portion of the silo. Simple diagram description

[0007] [Figure 1] Schematic illustration of a green energy steam system for generating superheated steam.

[0008] [ FIG. 2 ] Diagrammatically illustrates a more detailed view of the heat exchanger module of the illustrative green steam system of FIG. 1 .

[0009] [Figure 3] A diagrammatic illustration of a suitable water / steam circuit for the system of Figures 1 and 2. Implementation Method

[0010] The steam generation system and method disclosed herein provides saturated or superheated steam for use in industrial processes from renewable energy sources, such as solar or wind power. Therefore, this steam generation system is also referred to herein as a green steam system. Solid particles are used to absorb and store energy from available renewable energy sources. When steam is needed, energy is transferred from the solid particles to a heat transfer fluid in a suitably designed heat exchanger. In embodiments where the heat transfer fluid is water, steam is generated directly and delivered to the industrial process. In embodiments where the heat transfer fluid is not water, a second heat exchanger is suitably used to generate steam from the hot heat transfer fluid. The green steam system is flexible and can be configured with different heat transfer surfaces for different applications. A non-limiting, illustrative example configuration for generating superheated process steam is described below.

[0011] Referring to FIG. 1 , an illustrative green steam system is shown. FIG. 1 also shows an industrial facility F operatively connected to the illustrative green steam system, with ground level G indicated by an illustrative truck T positioned there. In this system, sand or other granular material is gravity-fed through an electric heater 10, where the particle temperature is raised to (in one non-limiting illustrative embodiment) between 600°C (1112°F) and 650°C (1202°F). The temperature to which the granular material is heated is controlled by the rate at which the granular material is conveyed and the power supplied to the heater 10 (i.e., how hot the heater 10 is operated). In some embodiments, these parameters are set to ensure that the granular material is heated to a temperature of at least 600°C.

[0012] An electric heater 10 operates using renewable energy and is positioned above an insulated silo 12 where hot sand is stored. Therefore, the insulated silo 12 is also referred to herein as a hot silo 12 or hot sand silo 12. The illustrative heater 10 is positioned above the silo 12, between the hopper 14 and the top 12T of the silo 12; however, it is also contemplated that the heater could be integrated into the upper portion of the silo. By way of non-limiting illustrative example, the electricity to operate the electric heater 10 can be generated by a renewable energy source, such as solar energy generated by photovoltaic solar panels, solar thermal collectors, concentrated solar power systems, etc.; wind energy generated by wind turbines, etc.; or another type of renewable energy source. Hot sand particles exit the bottom 12B of the silo 12 and flow by gravity through a plurality of heat exchanger modules 20, 22, 24, and 26, where the sand transfers its energy to water and steam. The sand exits the heat exchanger modules 20, 22, 24, 26 as cold sand at a temperature between 150°C (302°F) and 200°C (392°F) (in one non-limiting illustrative embodiment) and is transported to a bucket elevator or other sand delivery system 30, which lifts the cold sand to the top 40T of a second insulated silo 40, also referred to herein as a cold sand silo 40, a cold silo 40, or a storage silo 40. In the illustrative example, the sand delivery system 30 lifts the cold sand to a hopper 42 at the top 40T of the second insulated silo 40. In some embodiments, the delivery of granular material, the delivery of electricity, and the flow of heat transfer fluid can be adjusted to cool the granular material exiting the bottom 12B of the hot silo 12 to a temperature of 200°C or less. When renewable energy is available for the electric heater 10, sand is removed from the bottom 40B of the second (i.e., storage) silo 40 by a screw conveyor or other sand delivery system and fed to a bucket elevator or other sand delivery system 44, which raises the sand to the inlet of the electric heater 10 (e.g., in the illustrative example of FIG. 1 , the sand is delivered by the sand delivery system 44 to the hopper 14 positioned above the heater 10).

[0013] Referring to FIG2 , a more detailed view of the heat exchanger modules 20, 22, 24, and 26 of the illustrative green energy steam system of FIG1 is shown. The illustrative heat exchanger modules are arranged in two parallel particle flow paths P1 and P2. Particle flow path P1 is also referred to herein as sand flow path #1; similarly, particle flow path P2 is also referred to herein as sand flow path #2. Each particle flow path P1 and P2 comprises at least two heat exchanger modules arranged in series. In the first flow path P1 ("sand flow path #1"), sand passes through a generator module 20 to produce saturated steam, and then through an economizer module 22 to heat the feed water to near saturation. In the second flow path P2 ("sand flow path #2"), sand passes through a superheater module 24 to produce superheated steam, and then through a second economizer module 26 to heat the feed water to near saturation. During operation, all heat exchanger modules 20, 22, 24, 26 are filled with slow-moving, loosely packed sand particles.

[0014] The production row module 20 and superheater module 24 are designed with vertically oriented heat exchanger tubes, as schematically shown in FIG2 , parallel to the direction of sand flow (i.e., parallel to flow paths P1 and P2). This advantageously reduces the flow resistance to the sand due to the heat exchanger tubes of the production row module 20 and superheater module 24. The heat exchanger tubes of the production row module 20 are connected to an inlet header 20 In at the bottom of the production row module 20 and an outlet header 20 Out at the top of the production row module 20. Similarly, the heat exchanger tubes of the superheater module 24 are connected to an inlet header 24 In at the bottom of the superheater module 24 and an outlet header 24 Out at the top of the superheater module 24. This provides a water / steam flow countercurrent to the sand flow (i.e., countercurrent to the direction of sand flow paths P1 and P2). This countercurrent arrangement advantageously maximizes heat transfer from the hot sand to the water / steam. The headers 20 In, 20 Out, 24 In, 24 Out, and the connecting pipes are suitably covered with refractory material to protect them from erosion caused by the sand flow. The heat transfer pipes are arranged in staggered bundles. Flow disruptors are optionally attached to each pipe in a manner that moves cooled sand away from the outer pipe wall and hot sand toward it. As two non-limiting examples, the optional flow disruptors cover the entire surface of each pipe and can be either a pin or fin design.

[0015] In some non-limiting illustrative embodiments, economizer modules 22 and 26 are designed with heat exchanger tubes oriented horizontally, as schematically shown in FIG2 , and parallel to the long axis of the module. The tubes are connected in a serpentine pattern to tubes connected to tubes at the next higher elevation using "U-shaped" straps. The tubes are arranged in staggered bundles when viewed from the ends of the tubes. The staggered bundles help keep the sand mixed, allowing the tubes to see a more uniform sand temperature. The tubes are connected to the inlet header at the bottom of the module and to the outlet header (not shown in FIG2 ) at the top of the module. This provides an overall water flow that is opposite to the sand flow, even when each individual tube is in a cross-flow configuration.

[0016] In the illustrated embodiment, the bottom of each economizer module 22 and 26 includes an auger 50 oriented parallel to the long axis of the economizer module. The auger 50 is adjacent to one another with no gaps between them. The auger 50 controls the flow of sand through the heat exchanger modules 20, 22, 24, and 26 by removing sand from the bottom of the economizer modules 22 and 26 and transporting it to the inlet (e.g., hopper 42) of the cooling silo bucket elevator 30 (see FIG. 1 ). Because there are multiple auger 50, the sand flow in the vertical lane corresponding to each auger 50 can be independently adjusted to address uneven sand temperature distribution or flow imbalances within the heat exchangers 20, 22, 24, and 26. While parallel auger 50 is illustrated, other types of sand transport are contemplated in alternative embodiments, such as a row of parallel conveyor belts oriented perpendicular to the long axis of the economizer modules 22 and 26.

[0017] FIG2 shows a vertical channel 52, referred to herein as a silo drain 52, positioned below the centerline of the hot silo 12 between the heat exchanger modules 20, 22 of the first particle flow path P1 and the heat exchanger modules 24, 26 of the second particle flow path P2. This vertical channel 52 provides a sand flow path P3 that feeds one of the screw conveyors 50 (as shown, or optionally, multiple screw conveyors). The silo drain 52 is used to remove sand from the hot silo 12 during maintenance activities, extended downtime, or when there is a need to quickly remove hot sand. The screw conveyors 50 are water-cooled and transport sand to the inlet of the cooling silo bucket elevator 30 (see FIG1). Under normal operating conditions, the drain 52 is filled with sand that does not move.

[0018] Referring to FIG3 , a water / steam circuit is shown, suitably employed in the illustrative green energy steam system of FIG1 and FIG2 . Warm condensate returns from an industrial process (e.g., the illustrative industrial facility F shown in FIG1 ) via piping 60 , etc., and is mixed with fresh makeup water delivered via water line 61 . The mixture is then delivered via piping 62 , etc. to the inlet of a feed pump 64 (also indicated in FIG1 ). Downstream of the feed pump, the high-pressure water is split into parallel streams 66 and 68 , which are routed through two economizer modules 22 and 26 (e.g., economizer banks 1 and 2 in FIG2 ). Nearly saturated water exits economizer modules 22 and 26 and is routed via riser 69 to a steam separator 70 (also indicated in FIG1 ), which in the illustrative example is a vertical separator 70. Water exits the bottom 70B of the vertical separator 70 and travels through downcomers 71 to the inlet header 20In of the production row module 20. The saturated steam / water mixture exits the production row module 20 at the outlet header 20Out and returns to the vertical separator 70 via risers 72. This establishes a natural circulation loop, where flow is driven by the density difference between the separator 70 and the production row 20. The vertical separator 70 also has a blowdown line 76 where water can be removed from the system to control the accumulation of dissolved solids in the system. In the illustrative embodiment, the vertical separator 70 is used in place of a steam drum because it has a better form factor for green steam applications (e.g., it can be easily mounted on a hot silo 12, as schematically shown in FIG1 ) and because it responds more quickly to changes in steam demand. However, alternatives to the illustrative vertical separator 70, such as steam drums, are contemplated.

[0019] Saturated steam exits the top 70T of the vertical separator 70 and proceeds through pipes 78 and other lines to a steam collector 80 (also indicated in FIG1 ) before flowing through the superheater module 24 into its inlet header 24In. The superheated steam exiting the outlet header 24Out of the superheater module 24 is sent to the industrial process F (labeled "Steam to Process" in FIG3 ) via pipes 82 and other lines. The steam collector 80 is used in the illustrative green steam system to provide a faster response to changes in steam demand than could be achieved by varying the sand flow. When the system produces more steam than is required by the industrial process F, the excess steam is stored in the collector 80. The stored steam can be released later to meet a rapid increase in steam demand or to fill any gaps in the availability of renewable energy.

[0020] The green steam system can also be configured to deliver saturated steam instead of superheated steam by using a second generation bank module instead of the superheater module 24 .

[0021] In some embodiments, the heat exchanger modules 20, 22, 24, 26 may be self-contained devices that can be disconnected from the system and removed via a monorail system for maintenance or replacement.

[0022] The illustrative heat exchanger module is arranged in two particle flow paths. However, more than two sand paths are also contemplated for use in green steam systems.

[0023] The illustrative example uses sand as the granular material. Sand is advantageous in terms of low cost, high heat capacity, and good flowability. However, other granular materials are also contemplated for use in green steam systems, such as gravel, crushed stone, and synthetic granular materials.

[0024] While the foregoing description constitutes a preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation, and alteration without departing from the proper scope and fair meaning of the appended claims.

[0025] 10: (Electric) Heater 12: (insulated) silo (hot silo) 12 B: bottom 12 T: Top 14: Hopper 20: Heat exchanger module (generating row module) 20 In:Inlet pipe header 20 Out: Export header 22: Heat exchanger module (economizer module) 24: Heat exchanger module (superheater module) 24 In:Inlet pipe header 24 Out: Export header 26: Heat exchanger module (second heat exchanger module) 30: Sand transfer system (cooling silo bucket lifter) 40: Second (insulated) silo 40 B: bottom 40 T: Top 42: Hopper 44:Sand delivery system 50:Screw conveyor 52: Vertical channel (silo discharge channel) 60: Pipeline 61: Waterline 62: Pipeline 64: Feed pump 66: Liquid Flow 68: Liquid Flow 69: Rising pipe 70: Steam (vertical) separator 70 B: bottom 70 T: Top 71: Downcomer 72: Rising pipe 76: Discharge pipe 78: Pipeline 80: Steam collector 82: Pipeline F: Industrial facilities (industrial processes) G: Ground level P1: Particle (first) flow path P2: Particle (second) flow path P3: Sand flow path

Claims

1. A steam generation system, comprising: A silo, configured to receive granular material in the upper part of the silo; A heater is arranged at or within the upper portion of the silo to heat the granular material received in the silo; a material transfer system is arranged to remove the granular material exiting from the bottom of the silo. A heat exchanger is disposed in the lower portion of the silo and arranged to contact granular material flowing downward into the silo, wherein the heat exchanger includes at least one row of heat exchanger tubes; a steam separator or steam drum is operatively connected to the at least one row of heat exchanger tubes; a superheater is connected to receive water or steam from the steam separator or steam drum; and a steam collector is inserted between the steam separator or steam drum and the superheater.

2. As in request item 1, the steam generation system, wherein, The heat exchanger tubes in at least one row are oriented vertically.

3. As in request item 2, the steam generation system, wherein, The heat exchanger also includes at least one heat-saving device disposed below the at least one row of heat exchanger tubes.

4. As in request item 3, the steam generation system, wherein, The tubes of the at least one heat saver are horizontal, and the material transfer system includes a plurality of parallel spiral conveyors or conveyor belts arranged parallel to the horizontal tubes of the at least one heat saver.

5. The steam generation system of claim 1 further includes: A storage silo is connected to receive, at the upper portion of the storage silo, granular material removed from the silo by means of the material transfer system, and to transfer granular material from the storage silo to the upper portion of the silo.

6. A method for generating steam, comprising: Provide a steam generation system as requested in item 1; connect a steam collector to collect the steam output from the steam separator or the steam drum; The granular material is conveyed to the upper part of the silo of the steam generation system; electricity is supplied to operate the heater of the steam generation system; and heat exchanger allows heat transfer fluid to flow through the steam generation system.

7. As in request item 6, the method for generating steam, wherein, The transport of the granular material, the transport of electricity, and the flow of the heat transfer fluid are performed simultaneously.

8. As in request item 6, the method for generating steam, wherein, The granular material being transported includes sand.

9. As in request item 6, the method for generating steam, wherein, The transmission of the power used to operate the heater includes generating the power from solar or wind energy.

10. The steam generation method as described in claim 6, wherein, The delivery of the granular material and the delivery of the electricity are effective for heating the granular material to a temperature of at least 600°C.

11. As in request item 6, the method for generating steam, wherein, The conveying of the granular material, the transmission of electricity, and the flow of the heat transfer fluid are effective in cooling the granular material exiting the bottom of the silo to a temperature of 200°C or lower.

12. A steam generation system, comprising: A silo, configured to receive granular material in the upper part of the silo; A heater is arranged to heat the received granular material to produce heated granular material; A heat exchanger is disposed in the lower portion of the silo and arranged to extract heat from the heated granular material flowing downward into the silo to produce cooled granular material, wherein the heat exchanger includes at least one row of heat exchanger tubes; a material transfer system is arranged to remove the cooled granular material exiting from the bottom of the silo. A storage silo is connected to store the cooled granular material removed by the material transfer system, and to transfer the granular material from the storage silo to the upper portion of the silo; a steam separator or steam drum is operatively connected to the at least one row of heat exchanger tubes; and a steam collector is connected to collect steam output from the steam separator or the steam drum; wherein the heat exchanger further includes a superheater connected to receive steam from the steam collector.

13. The steam generation system as described in claim 12, wherein, The heat exchanger includes at least one row of heat exchanger tubes oriented vertically.

14. The steam generation system as described in claim 13, wherein, The heat exchanger also includes at least one heat-saving device, which comprises horizontally oriented tubes disposed below the at least one row of heat exchanger tubes.

15. The steam generation system as described in claim 14, wherein, The material transfer system includes a plurality of parallel spiral conveyors or conveyor belts arranged parallel to the horizontally oriented tubes of the at least one heat exchanger.

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